If it's bad, go to a derm to try a prescription retinoid (adapalene, tret or taz). They may start on an antibiotic to keep the acne at bay until the retinoid kicks in fully.
If things don't get better, accutane is the nuclear option where they shut down the sebaceous glands body-wide.
But lots of people can manage on tret or taz and don't need to do that option.
If it's not too bad, a skin regimen helps. Salicylic acid is great to slough off the skin cells where acne gets trapped (oil/bacteria) underneath.