How to prevent FUTURE acne or clogged pores?

How can I prevent or make acne or clogged pores disappear, or how do I stop them in the future? Should I change my dietary foods, etc.? My prom is in 4 days and I have acne all over my face. what should I use/do to prevent future breakouts and clogged pore? Is there a way to make my pores close up or make it smaller?I am going to the prom with my bf, so I don't want to be the only one with acne... PLEASE DO NOT SAY "USE ACNEACE!!!!" Only tell me products I can actually buy at target and local common store. Thanks...