Acne Scars and Pigmentation: What's the Treatment Order?

When brown pigmentation and pitted scars from acne show up together, the safer path is usually to calm any active breakouts first, let the pigmentation settle, and only then move into collagen-rebuilding treatment for the pitted marks. Flat pigmentation often fades on its own over time, while pitted scars rarely resolve without treatment, so the two marks need separate diagnosis and separate tools. Because skin that tans easily tends to re-pigment after heat-based treatment, the intensity and spacing of scar treatment have to be adjusted to how the pigmentation is behaving.

Hello, I am Dr. Kyungsu Kim, director of the Seocho branch of UH CELL Clinic. I graduated from Seoul National University College of Medicine and hold medical licenses in both Korea and Japan. At the Seocho branch, located at UH FLAT The Seocho on Banpo-daero 16-gil, I see patients whose acne left more than one kind of mark on the same area of skin. When pigmentation and pitted scarring overlap, the order in which I treat them shapes both the result and how much downtime a patient needs. Here is how I decide that order, and where the evidence behind it stops.

Two Marks, Two Different Mechanisms

The American Academy of Dermatology (AAD) draws a line between true scarring and the flat marks that remain after acne clears, and identifies post-inflammatory hyperpigmentation (PIH) as the most common of these flat marks. According to the AAD, patients with lighter skin tones often see these marks as red or pink, while patients with medium to deeper skin tones more often see brown. The AAD notes that this pigmentation usually fades with time, and treatment can help it fade faster.

Pitted scars behave differently. The same organization explains that depressed scars are the most common form of acne scarring, and that while they can become less noticeable, they rarely disappear completely on their own. Pigmentation is a problem of melanin near the skin's surface. A pitted scar is the result of damaged collagen structure deeper in the dermis. A tool built to fade pigment will not rebuild that structure, and a tool built to rebuild collagen will not by itself calm pigment.

During a consultation, I document each mark separately. I note whether it carries color, whether it sits below the surrounding skin surface, and whether new inflammation is still active. Many patients have both color and texture change in the same spot, and that overlap is where planning has to start.

The Four-Step Order I Use in Consultations

The AAD recommends starting acne treatment as soon as it appears and staying consistent, as a way to reduce the risk of scarring. Treating scars while new breakouts keep appearing means new marks keep forming next to the ones already being treated.

In the second step, I look at whether pigmentation is actively darkening or already fading. The purpose of this step is timing: I avoid adding a strong heat-based treatment while pigment is still progressing. Once pigmentation shifts toward fading, I begin considering scar treatment.

The third step is where I address pitted scars directly. For mild scarring, the AAD notes that topical treatments such as retinoids or salicylic acid can make scars less noticeable on their own. More pronounced pitted scarring usually needs a procedure that stimulates collagen regeneration.

Why I Don't Rush Scar Treatment While Pigmentation Is Active

The lasers and radiofrequency devices used for scar treatment work by deliberately creating micro-injury and heat to trigger collagen regeneration. When that stimulation also activates melanin-producing cells, it can create new pigmentation at the treated site. A study in Acta Dermato-Venereologica focused on Asian patients found that post-inflammatory hyperpigmentation was the most common side effect of laser treatment in people with darker skin.

The risk is more pronounced with ablative lasers. A 2025 paper in the Journal of Cosmetic Dermatology, citing earlier reports, noted that pigmentation can appear in up to 92% of patients with Fitzpatrick skin type IV or higher after ablative CO2 laser treatment. The same paper explained that non-ablative fractional lasers and radiofrequency microneedling carry a lower pigmentation risk, but do not match CO2 laser's depth of dermal remodeling.

Research on Korean patients points in a similar direction. A study available through the U.S. National Library of Medicine's PMC treated 24 patients with Fitzpatrick skin types IV and V, all with acne scars and wrinkles, with a single session of CO2 fractional laser. Two of them developed pigmentation about a month after treatment, which faded by around the three-month mark. When a patient's skin already carries active pigmentation, an added reaction like this extends the recovery period they actually experience.

Matching Intensity and Interval to Pigment Response

Every scar-treatment tool balances effectiveness against pigmentation risk differently. A 2025 retrospective study available through PMC analyzed 397 Asian patients with atrophic acne scars and found pigmentation in 5.42% of those treated with fractional laser and 4.71% of those treated with fractional radiofrequency, a difference the researchers did not consider statistically meaningful. Both groups showed clinically meaningful improvement, and the radiofrequency group reported more pain during treatment.

Even the same device can produce different outcomes depending on how it is used. A retrospective study of Asian acne scar patients published through PubMed found that using non-ablative fractional laser at high density carried an 18.2% pigmentation risk, compared to 6.0% when density and the number of passes were reduced. The study found no statistically confirmed difference in effectiveness between three high-density sessions and six low-density sessions. This is why lowering intensity and spreading treatment across more sessions matters for skin that pigments easily.

The AAD describes microneedling as safe for all skin tones and notes it is often combined with other treatments such as radiofrequency or chemical peels. Mayo Clinic explains that laser resurfacing carries a higher risk of side effects in patients with darker skin or a history of keloid scarring, and that energy-based treatments like radiofrequency tend to produce more subtle results that may require repeated sessions.

With that in mind, I choose the device, intensity, and interval based on scar depth and shape, pigment status, any keloid history, and how much downtime a patient can tolerate. I explain the specific equipment and combination I recommend, and why, during the in-person consultation at the Seocho branch, after examining the skin directly. As stated in our official guidance, the devices, injectables, and medications used here are genuine, and packaging is opened in front of the patient before treatment begins.

Where the Evidence Ends

Large randomized controlled trials on treating post-acne pigmentation are still limited. A 2023 paper in the Journal of the American Academy of Dermatology (JAAD) noted this gap and described how a panel of ten dermatologists used a Delphi consensus process to reach agreement on first-line treatment recommendations, in the absence of that stronger evidence.

The four-step order I described above is not a formula proven by a large clinical trial either. It is a clinical judgment built on the AAD's recommendation that controlling acne helps prevent scarring, together with research showing that scar treatment itself can trigger pigmentation. For patients with mild pigmentation and mild scarring, I sometimes overlap steps two and three. For patients whose pigmentation reacts strongly, I push step three back further. The order is a principle; the pace is set by how the skin actually responds.

For Patients Visiting Seoul on a Short Trip

Many patients who travel from abroad have limited time in Seoul. Scar treatment is usually delivered across multiple sessions, with recovery time needed between them, so completing all four steps in a single visit is rarely realistic.

In these cases, I find it helpful to set a clear goal for the first visit. We diagnose the type of marks present, decide what can be addressed now, and plan what should wait until a return visit. I also factor in that a strong scar treatment scheduled right before a flight home makes it harder to monitor a pigment reaction if one appears. Holding both Korean and Japanese medical licenses lets me discuss follow-up care with patients coming from Japan in a way that accounts for both countries' treatment settings.

What to Do in the First Week After Treatment

Reducing new pigmentation after scar treatment depends as much on aftercare as on the procedure itself. Our official Seocho guidance recommends consistent sun protection and moisturizing, and advises avoiding saunas, hot springs, strenuous exercise, alcohol, and smoking for about a week. Precautions can vary or add up depending on the specific procedure performed, so patients should confirm the guidance that applies to their own treatment.

FAQ

Is redness after acne also considered pigmentation?

According to the AAD, patients with lighter skin tones may see flat post-acne marks appear red or pink, and the AAD classifies these flat marks separately from true scarring. That said, redness and brown discoloration can have different causes and different management, so I assess the color and distribution of each mark directly during consultation.

If new brown marks appear after scar treatment, does that mean I now have a scar?

New brown marks that appear after treatment are usually post-inflammatory pigmentation, and the AAD explains that these flat marks generally fade over time. In the Korean patient study referenced earlier, pigmentation that appeared a month after treatment had faded by around three months. If a mark darkens further or persists longer than expected, I adjust intensity and interval before the next session.

Can I still get scar treatment if I'm prone to keloid scarring?

Mayo Clinic notes that patients with a history of keloid scarring face a higher risk of side effects from laser resurfacing. This history changes which tools are appropriate, so please tell me during consultation if you have ever had a wound heal by raising into a thick, raised scar.

How many sessions does scar treatment usually take?

The number of sessions depends on scar depth, the device used, and how the skin responds to pigment stimulation, so I can't commit to a fixed number in advance. The AAD notes that the number of sessions needed varies by laser type, and Mayo Clinic explains that energy-based treatments such as radiofrequency may require repeated sessions. At the first diagnosis, I give patients an expected range and adjust the plan session by session based on how the skin is actually responding.

Skin response and recovery time vary between individuals. For an accurate diagnosis and treatment plan, please consult with a physician directly.