12. Step away from your hands. You know how you rest your face on your hand while you're studying? That might be the reason for those blemishes on your cheek or jaw. You're constantly touching things that have germs—anything from your phone to your locker—so putting your hands on your face for a long period of time can cause dirt and bacteria from anything you touch to get into your pores.
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.