Acne Scars vs Dark Marks (PIH): How to Tell the Difference
Many people assume that any mark left after acne is a scar. In reality, most marks that remain after pimples heal are not true scars.
Dermatologists typically separate these into two categories:
- Acne scars — structural changes in the skin
- Post-inflammatory hyperpigmentation (PIH) — color changes after inflammation
Understanding the difference matters because the treatment approaches are completely different.
What Are Acne Scars?
Acne scars occur when inflammation damages deeper layers of the skin and healing alters the skin’s structure.
Typical features of true acne scars include:
- Permanent texture change
- Indentations or raised areas in the skin
- Shadows under side lighting
- Skin surface feels uneven to the touch
Common scar types dermatologists see include ice-pick scars, boxcar scars, and rolling scars.
Unlike pigmentation marks, true acne scars generally do not fade completely on their own.
What Is Post-Inflammatory Hyperpigmentation (PIH)?
PIH refers to color changes left behind after acne inflammation resolves. The skin surface remains smooth, but pigment production increases in the affected area.
These marks may appear:
- Red or pink
- Brown
- Purple or dark gray in deeper skin tones
Unlike scars, PIH is flat and usually fades gradually over several months, although sun exposure can slow the process.
Quick Self-Test: Scar or Pigmentation?
One simple trick is to look at the skin under angled lighting.
- If the mark creates a shadow or depression → likely a scar
- If the skin surface is smooth but the color is darker or red → likely PIH
Treatment Approaches Are Different
Treating PIH
- Sun protection
- Retinoids
- Azelaic acid
- Gentle chemical exfoliation
Treating Acne Scars
Because structural scars involve deeper skin layers, treatment often involves procedures such as:
- Microneedling
- Laser resurfacing
- Subcision
- Chemical peels
Topical skincare alone usually cannot fully correct structural scars.
Preventing Both
The best prevention strategy is controlling acne early and consistently.
If you're unsure how long acne treatments typically take to work, see our guide on realistic acne treatment timelines.
Want a dermatologist-written acne plan based on your photos?
Adults physically located in Texas or Washington can request a dermatologist-led asynchronous acne evaluation. You’ll receive a structured written plan within 24 hours (business days).
Start Acne Review ($39)Prescriptions are not provided through this service at this time. If, after review, we determine that care cannot be safely provided through this format, a full refund will be issued.
Educational information only. Not medical emergency care.