Acne-like bumps on the back are considered to be related to the occurrence of oily seborrhea or folliculitis, acne and other diseases. 1. Oily sebaceous overflow: after wiping the sebaceous overflow area on the face and back, the sebum will soon be overflowed again. If the sebum is not cleaned in time, the sebaceous sebum will adhere with dust and keratin, and there will be accumulation of sebum, the mouth of the hair follicle will be enlarged and filled up by the sebaceous plugs, so that pimples can be seen, and the hand can be extruded to produce soft white sebum or to form hard sebaceous plugs. 2. Folliculitis: Bacterial infection can be induced in the follicular opening on the back due to poor hygiene, high temperature, excessive sweating or scratching, etc. Red follicular papules appear on the skin at the beginning, which can be changed into pustules with red halo in a few days, and the pustules can leave yellow scabs when they break. 3. Acne: mostly occurs in young people, due to the imbalance of estrogen and androgen levels in the body or high levels of androgens, sebaceous gland secretion increases, in the growth of Propionibacterium acnes there are keratin plugs and sebum accumulating in the follicular opening, the formation of back follicular opening pimples, inflammatory papules or pustules and other skin lesions. The appearance of acne-like bumps on the back, in addition to ensuring that the skin is clean, it is also recommended to consult a doctor in a timely manner and follow the doctor’s instructions for medication.