ANDY'S ANSWER: Using makeup is probably not helping your pimples, particularly if it is oil-based. Acne can be at its worst when you are going through puberty because your hormones generate an over-abundance of sebum. The sebum clogs the pores around the hair folicles and bacteria sets in, which can infect causing swelling and tenderness.
If you are using products or creams on your face, look for ones that won't clog your pores. The label should say that they are non-comedogenic.
The best thing you can do is gently wash your face with a mild cleaner and exfoliate once or twice a week with a facial scrub to remove dead skin cells which can mix in with the sebum to cause even more clogged pores and pimples.
There are a number of over-the-counter medications you can also use to help (make sure you use according to the directions), and if your acne is severe, you should talk to a doctor who may prescribe something stronger.