Sometimes even though they wash properly and try lotions and oil-free makeup, people get acne anyway — and this is totally normal. In fact, some girls who normally have a handle on their acne may find that it comes out a few days before they get their period. This is called premenstrual acne, and about 7 out of 10 women get it from changes in hormones in the body.
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.