Some acne marks and scars are completely within your control while others are pre-determined. Aside from genetics, there are several lifestyle habits that can make dark marks and scars worse. Spending time in the sun is a big one, and, to reiterate one last time, every dermatologist agrees that picking or squeezing pimples creates further inflammation and can ultimately lead to more damage.
Acne (acne vulgaris, common acne) is a disease of the hair follicles of the face, chest, and back that affects almost all teenagers during puberty -- the only exception being members of a few primitive Neolithic tribes living in isolation. It is not caused by bacteria, although bacteria play a role in its development. It is not unusual for some women to develop acne in their mid- to late-20s.