Back Acne (Bacne) develops when the skin hair pores become clogged with dead skin, sweat, or dirt mixed with oil known as sebum made by oil-producing glands. Acne can form anywhere on your skin, including your back.
Acne happens when oil, dirt, dead skin cells and bacteria clog your skin’s pores. Back acne usually results when sweat gets trapped under a shirt or athletic gear during exercise or strenuous activity. Clothing rubs against your sweaty skin, which leads to zits or makes them worse.