When a pore becomes clogged with oil, dead skin cells and bacteria, it can swell and rupture beneath the surface. If that inflammation reaches the deeper layers of the skin, the body repairs the damage by producing new collagen — but this repair is often imperfect.
- Too little collagen during healing leaves a depression, producing an atrophic (sunken) scar.
- Too much collagen produces a raised hypertrophic scar or a keloid.
Several factors raise the potential risk of scarring: severe or cystic acne, delayed treatment of active acne, picking or squeezing spots, and a family history of scarring. This is why managing active acne early is an important preventive step — the longer and more severe the inflammation, the higher the potential for persistent structural scarring.