After a pimple heals, some people are left with lingering dark spots or uneven pigmentation. These marks are known as post-inflammatory hyperpigmentation (PIH) and occur when the skin produces excess melanin as part of the inflammatory healing response.

Unlike scars, PIH does not involve permanent structural damage, but it can take weeks to months to fade without targeted treatment.

PIH develops when inflammation from a breakout stimulates localised pigment production. Several factors influence how dark and persistent these marks become:

• Severity of inflammation
  Deeper or more inflamed breakouts trigger greater melanin production.
  
• Picking or squeezing
  Trauma intensifies inflammation and disrupts healing, prolonging pigmentation.
  
• UV exposure
  Sunlight stimulates melanocytes, causing dark marks to deepen and persist.
  
• Skin tone
  Medium to deep skin tones are more prone to PIH due to higher baseline melanin activity.
  
• Delayed healing or barrier impairment
  Repeated breakouts or a weakened skin barrier can extend the pigmentation process.
  

Targeted topical treatment can significantly accelerate fading by calming inflammation, regulating melanin production, and encouraging healthy cell turnover.