To treat back acne, start with an over-the-counter body wash containing benzoyl peroxide (5% to 10%) or salicylic acid (2%). Apply it daily in the shower, letting it sit on your skin for a few minutes before rinsing. For persistent acne, applying a topical retinoid like adapalene gel at night can help prevent new breakouts. Keep the area clean, shower immediately after sweating, and wear loose-fitting cotton clothing. If your acne is severe, painful, or causing scars, please consult a dermatologist. They can safely prescribe stronger options, such as topical or oral antibiotics, tailored to your skin.