The best thing you can do is to keep your pores from getting clogged. This can be accomplished by using a wash cloth or better still a Loofah also spelled loofa when showering. Some soaps clog your pores. Other than this diet changes and as is sometimes necessary medication.
Not going to work with the deep sebaceous glands on the back & shoulders. Anabolics can turn these into the typical monster cysts that some guys get via the DHT conversion that makes the glands go haywire. If it gets really bad, accutane is about the only thing that works. Antibiotics, scrubbing, and special shampoos won't make a dent in a lot of cases.