Use an exfoliating glove and a cleanser with 2% salicylic acid while you’re in the shower. Make sure to replace your gloves at least once every 3 months as they are breeding grounds for bacteria.  Soaps containing these ingredients serve as shedding agents, which will help to curb acne. If you scrub too roughly, you'll deplete your skin's natural oils, and you'll irritate your acne. Always scrub your chest gently to get rid of dead skin cells. Take a shower every day. If you don't clean your skin, you invite sebum and bacteria to collect on its surface, causing acne. " The cream should have a concentration of salicylic acid between 0.5 and 2 percent. Smear the cream directly over your acne to dry out and heal spots quicker. Benzoyl peroxide fights the bacteria that cause acne, and assists in drying out and peeling dead layers of skin on the epidermis. Exfoliating is removing the dead layers of skin on the epidermis, or the top layer of skin. Exfoliating can help decrease the incidence of chest acne and help acne marks fade. Chest acne is often the result of clogged hair follicles or pores, which causes sebum to build up. This ultimately leads to acne. Men tend to have chests covered with hair while women tend to wear more tight-fitting bras and tops. Both of these may contribute to chest acne, making exfoliation very important and make sure to wipe down with a cleansing toilette or toner after excessive sweating during a workout. Look for masks made of mud or charcoal or try a mask that contains mandelic acid.   Mud or charcoal mask. Rub this mask on your chest twice per week and then rinse it off. A mask will cleanse the area and unclog your pores.   Mandelic acid mask. These masks are usually applied 10 to 15 minutes before a shower. Then, you'll rinse the mask off with some specially formulated acne wash. You can also try a clay-based mask or a mask containing tea tree oil. Many people think that tea tree oil is a good treatment for a variety of skin conditions. Aspirin actually contains salicylic acid,...

TL;DR in Vietnamese:
Chọn sữa tắm giúp chống mụn trứng cá. Thoa "kem trị mụn". Dùng benzoyl peroxide. Tẩy tế bào chết. Đắp mặt nạ. Trộn hỗn hợp aspirin.