Acne is extremely common, but not every breakout is the same. When blemishes become deep, painful, or develop into large nodules and cysts beneath the skin, dermatologists consider this more serious because these types of breakouts have a greater chance of leaving permanent scars.
Cysts and nodules form when inflammation develops deep inside the skin. Unlike ordinary whiteheads or small pimples, they can feel tender or painful and may remain for much longer. Squeezing or picking them can worsen inflammation and increase the likelihood of scarring.
Acne can also appear for the first time during adulthood or continue long after the teenage years. Adult acne is not unusual, but a dermatologist can help when breakouts persist despite over-the-counter treatment or when they begin leaving dark marks or scars.

Sudden adult acne can sometimes deserve additional attention, particularly in women when it appears alongside symptoms such as irregular periods or increased facial or body hair, because hormonal changes may be involved. That does not mean every adult breakout signals an underlying condition, but a medical evaluation can help determine the cause.
The important thing is not to wait until severe acne has already caused lasting damage. Painful nodules, cysts, widespread inflammation, or visible scarring are good reasons to seek professional advice. Effective treatments are available, and early care can improve the skin while reducing the risk of permanent scars.
