Dark Marks vs Acne Scars (PIH vs Atrophic) — Different Layers, Different Care
People confuse post-acne dark marks (PIH) with acne scars — different skin layers, treated differently. Dr. Big explains how to tell them apart and treat each. Ratchathewi, near BTS.
“Why doesn’t my skin look smooth?” — many ask themselves in the mirror, seeing dark spots, red spots, or little grooves.
The problem: these 3 are treated differently but people can’t tell them apart:
- Post-acne dark marks (PIH — Post-Inflammatory Hyperpigmentation)
- Post-acne redness (PIE — Post-Inflammatory Erythema)
- Acne scars (Atrophic Scar)
Treat the wrong one and you apply creams for years with no result, or laser the wrong device and waste money. Dr. Big explains how to tell them apart — and how to treat each at the right skin layer.
A 30-second test
In angled 45° light, ask yourself:
Test 1: What color?
- Brown / black → dark marks (PIH)
- Red / pink → redness (PIE)
- Normal skin tone → likely a scar
Test 2: Smooth to the touch?
- Smooth, slides → dark marks/redness (on the surface)
- A dip, wave, or hole → an acne scar (in the skin)
Test 3: Gone in flat light?
- Gone → marks (a color issue)
- Still visible → a scar (a structural issue)
In reality, most people have all 3 mixed on one face — which is why assessment comes before treatment.
Post-acne dark marks (PIH) — causes
When acne inflames, melanocytes overproduce melanin to protect the skin; it accumulates in the epidermis and shallow dermis, becoming brown spots after the acne subsides.
Factors: Asian skin produces more melanin · sun without sunscreen · picking acne · oily skin + chronic clogged acne.
How long it self-clears
3–6 months (thin skin) · 6–12 months (normal) · 1–2 years (oily, no sunscreen).
What works
SPF50+ daily (most important) · Vitamin C 15–20% · Niacinamide 5–10% · Retinol/Tretinoin · AHA/BHA peel · Picolaser (in-clinic, 2–4 sessions) · Hydroquinone 2–4% (prescribed).
Dark marks treat better than scars — 3–6 months for a clear change with the right routine.
Post-acne redness (PIE) — causes
PIE is dilated capillaries after inflammation — pink/red spots where acne used to be. Not melanin — blood vessels · visible in fair/thin skin · may self-clear slower than PIH (6–24 months).
What works
SPF50+ · Niacinamide · Centella Asiatica · IPL · PDL (gold standard for PIE) · V-Beam.
⚠️ Picolaser doesn’t help PIE much — it targets pigment, not vessels.
Acne scars (atrophic) — causes
An acne scar is lost skin structure — deep into the dermis and sub-dermal, with tethering fibrous bands. Read What causes acne scars and Acne Scars: The Complete Guide.
What works
Subcision · MNRF · Ablative Fractional Laser · Picolaser (for dark marks at the base).
Acne scars don’t self-heal — unlike dark marks that gradually fade. See Do acne scars heal on their own.
Comparison table
| Problem | Color | Smooth? | Depth | Treated with | Time to clear |
|---|---|---|---|---|---|
| PIH (dark) | Brown/black | Smooth | Epidermis | Vitamin C, Pico, sunscreen | 3–12 months |
| PIE (red) | Red/pink | Smooth | Capillaries | IPL, PDL, Niacinamide | 6–24 months |
| Acne scar | Normal tone | Dipped/hole | Dermis-Sub | Subcision, MNRF, Ablative | 6–12 months + maintenance |
Frequently asked questions
Q: Can I have all 3 at once? A: Yes, very commonly — dark marks at a scar base + redness around it = all 3 in one spot.
Q: Can drugstore acne-mark creams treat scars? A: Most creams work in the epidermis — they help marks/redness but don’t reduce scar depth. Read Do 7-Eleven creams really treat acne scars.
Q: Which laser for brown dark marks? A: Pico Laser or Q-switched — they target pigment without harming surrounding skin.
Q: Can wrong laser make PIE worse? A: Strong Ablative Laser on PIE can flare inflammation → more redness · use a vascular laser specifically.
Q: Where can I consult or assess acne marks/scars near BTS? A: At Clarity Clinic Ratchathewi, near BTS Ratchathewi (1-min walk), easy to reach from Siam, Phaya Thai, all of Bangkok — Dr. Big assesses with a magnifier + Trica3D Scan to separate PIH/PIE/scars before treating, free 30-min consult.
Summary — where to start
- Mirror at home — roughly sort the type
- Start sunscreen + Vitamin C + Niacinamide daily (helps all types)
- Send a photo via LINE — free assessment of your case
- Plan in-clinic treatment — the right technique per layer. Most see a 60–80% improvement in 3–6 months with the right routine.
Contact:
- LINE: @clarityclinic — send a photo of your acne scars for Dr. Big to review
- Location: Spring Tower, B Floor · Ratchathewi, near BTS (Siam, Phaya Thai, all Bangkok)
- Free 30-minute consult with Dr. Big in person
- Price 5,000 baht/session including all main procedures + aftercare cream · pay per session, no course packages
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