What causes acne?
Acne happens to almost everyone at some point in their lives. It doesn't mean you are unclean or cursed -- it simply happens because of your hormones. These hormones can jump start your acne as early as the age of 8 (!) but things should calm down once you finish puberty.
Acne is caused by bacteria on the skin so most treatments are aimed at killing that bacteria (or stopping it from spreading). This means that some treatments can be hard on you skin. Here's something that will sound silly, but it's true. It is possible to scrub your skin too much! Don't wash your face or body with harsh soaps multiple times a day, and don't scrub so hard your skin becomes dry. Your skin has good oils that help fight bacteria, so scrubbing too much can actually make acne flare up.
Lastly, everyone's acne is different. You may find that your acne gets worse when you eat greasy foods or when you eat chocolate. If you want your acne to improve, you may want to cut out these "triggers." In addition, some ladies may find that acne flares with their period. If avoiding foods and basic home treatments do not significantly improve your acne, it's worth discussing prescription acne (and, for menstruating ladies, oral contraceptive) options with your doctor.