I have many pimples on my back. What happened?

1, mites. It is recommended to use soap and care products with acaricidal effect. 2. Scrub the back too hard when taking a bath, so that the delicate skin on the back loses its protective film and causes skin discomfort on the back. It is recommended to use mild bath cotton to control the intensity. 3, the air humidity is high, clothes are contaminated by microorganisms such as mold, which leads to skin allergies. It is suggested to choose antibacterial detergent or insolation when changing clothes to achieve sterilization effect. 4. Take a bath and change clothes frequently. Reasonable diet structure.