There are many causes of nipple entropion in the middle of the nipple. Nipple invagination is divided into congenital and acquired, congenital nipple invagination can be corrected by manual pulling, breast pump pulling or surgical methods. If congenital nipple invagination is caused by trauma, it can be left untreated, but if it affects life and aesthetics, it needs to be corrected. If nipple invagination is caused by breast cancer, it should be treated with high priority, active treatment of the primary disease, surgical removal of the breast, and regular chemotherapy after surgery. 2. Nipple wound. If the nipple has ever been cut, the seam may be a scar formation caused by a nipple wound, which does not need to be treated. 3. nipple cracking. For example, the nursing baby will bite through the nipple to form a wound, you can empty the milk to prevent infection and apply erythromycin ointment on the surface of the nipple.