Acne-like bumps on the buttocks are caused by inflammation of hair follicles, which is called folliculitis, can be caused by an infection from bacteria, yeast, or fungus, irritation of hair follicles, or blockage of hair follicles, she says.
Suggestion
Shower after a workout. Letting the sweat and dirt sit on your skin after a workout can be a big contributor to back acne. Exfoliate..Wear loose-fitting clothing. Try tea tree oil. Keep hair off your back. Choose sunscreen carefully. Eat healthy.
Medicine
its not advisible to provide medicine for online.