Person with red marks on their face

Why Does Acne Leave Red Marks

Acne can be stubborn. Even after a breakout is successfully treated, an acne blemish can leave a visible red mark. These red patches have a name: post inflammatory erythema (PIE). PIE is more likely to appear with stubborn acne than with mild cases. It’s also more visible on people with lighter skin tones, with scar coloration that ranges from pink to red to purple.1

PIE is caused when capillaries, the small blood vessels under the skin, become inflamed, dilated, or otherwise damaged. When acne stretches and damages the skin and the surrounding tissue, inflammation is the body’s natural response to initiate healing. If inflammation continues for longer than is needed to heal the blemish, it can damage the skin and induce redness and scarring.2,3

With inflammation, blood vessels around the lesion become dilated to provide nutrition to all the active cells in the lesion and in nearby inflamed skin. The dilation may take between 6 and 12 weeks to resolve, long after the acne itself has disappeared. So, a combination of inflammation, skin damage, and blood vessel dilation leads to PIE.2,3

The good news is that PIE is not permanent, and the red color will fade over time. If you or your teen is worried about any long-term effects of acne, a board-certified dermatologist can help you develop a skincare regimen that may help prevent PIE or permanent scarring.3 

One quick tip: a good way to prevent any long-term effects from pimples, including scarring, is to stop squeezing or picking pimples.4,5 We know it can be hard to resist the urge to pop a zit and offer some tips in our article, “How To Keep Your Teen From Popping Pimples…And Why You Should!


1. Healthline. How to treat post-inflammatory erythema. Reviewed December 4, 2020. Accessed July 5, 2022.