In your teens, pimples tend to affect oilier skin like on the forehead and T-zone. However, adult acne occurs on the cheeks, mouth and even chin, in the drier U-zone. It can be caused by various other factors, including:
- dehydrated skin
- sleep deprivation
- stress
When pores are blocked by dead skin cells, sebum and dirt, it can lead to pimple-causing bacteria multiplying and resulting in inflammation.