"Harmonal Imbalance" is the main reason behind having pimples on the face at teenage.
The problem of pimples is faced majorly by those who are having oily skin. Pimples also arise when you have digestion problem. To avoid pimples, wash your face with JUST Water, no face wash, no cream, nothing at all, it is as simple, at teenage, 4-5 times a day, don't worry washing face more times just doesn't hurt. Make sure you always keep your stomach CLEAN.
To cure pimples, simply keep a plant of aloe vera at your home and at the slightest hint of the pimple, put it on the pimple and the pimple will not grow further and will vanish.
By trying the above remedies, I don't think you will face any problem of pimple anymore. You will have a clean, glowing and baby soft (in case of girls! Wow!) skin.