Acne is caused by excessive sebum production, dead skin cells blocking hair follicles, and bacteria. It results in whiteheads, blackheads, heat, swelling, redness, and pain. Treatments include salicylic acid to remove dead skin cells, lactic acid to reduce sebum production, and benzoyl peroxide to treat bacteria. Following a routine with these ingredients as well as choosing non-comedogenic products, wearing oil-free makeup, drinking water, and getting enough sleep can help prevent acne.