First, know that you didn't do anything to cause your acne. Having acne doesn't mean your skin is dirty, or that you aren't doing a good job at cleansing your skin. In fact, overzealous cleansing and vigorous scrubbing can make breakouts worse, not better.
And you don't have to forgo chocolate or other sweets. A nutritious diet is important, but a few treats now and then aren't going to cause pimples.
Acne is caused by factors that are out of your control. Pimples begin deep down in the skin, where you can't see. Oil and dead skin cells block the pore, creating a blackhead or comedo. If bacteria invade, the follicle becomes red and swollen, and a pimple is formed.
During the teen years, major hormonal changes are occurring within the body. These hormones, specifically androgen hormones, rev up oil production. This explains why your skin is suddenly much more oily than it was when you were a little kid. And more oil means more pore blockages.
Using oily skin care products or heavy makeup can also trigger a form of acne called acne cosmetica. To avoid this type of acne, use only products labeled noncomedogenic or nonacnegenic. Use only light, oil-free moisturizers and sunscreens. If you use pomades or oils in your hair, keep it well away from the hairline. And remember to wash everything off at night before you go to bed.
Acne runs in families, so if either of your parents had acne you are more likely to have acne too. Most people outgrow acne, but for some people acne can last well into adulthood. Sometimes people even get acne for the very first time as adults.
This doesn't mean you have to wait for acne to go away on its own. Although acne can't be cured, it can be successfully cleared up with the right treatments. Over-the-counter products can help if you have mild acne or occasional pimples. Anything more persistent will probably need a prescription medication. There are a number of medications available that do a great job of clearing up teen acne. So talk to your parents and give your doctor a call!