I've never really had an acne problem but occasionally I get a blemish or two and it's usually because of what I'm eating. Things like sweets, red meat, alcohol, etc tend to have negative effects on my skin while eating only fish, chicken, salads, drinking a lot of water clears it up. If your diet is fine, I'd say try apricot scrub on your face to exfoliate and then use witch hazel.
If it's a severe case, I'd recommend a dermatologist and a nutritionist.