Reasons. 1. Excessive oil secretion the back is a dense sebaceous gland, more oil, and the summer weather is hot, oil secretion is more vigorous, coupled with the back cuticle is relatively thick, metabolism is much slower, accidentally blocked pores, acne naturally one out of the way. 2. Usually not thoroughly cleaned The back itself belongs to the blind spot of sight, it is difficult to thoroughly clean, and the back sweats too much, easy to breed bacteria, acne will come out. After bathing, the moisture is not sucked dry, easy to wet the clothes close to the body, not only easy to breed bacteria, but also the hair on the clothes may clog the pores on the back, more likely to acne. 3. Contact with dust Sometimes the bed is not cleaned properly, there is dust on it, after the back and the bed are in contact, the unclean dust will also block the pores, making oil form acne. 4. Skin allergies cause acne on the back Skin allergies can also make acne on the back. To find out the allergen, usually avoid letting the skin come into contact with the allergen. 4. Lung heat/meridian blockage The back is the reflection area of the lungs. Lung heat or meridian blockage will cause acne on the back. You can go to the red makeup club to experience the five elements of temperature, which can eliminate excess water, cold dampness and toxins in the human body. Please metabolize waste in the body and improve human metabolism.