There are many reasons for bumps on the side of the nipple, the most common reason is folliculitis, which is caused by bacterial infection of the local skin, the main manifestation is the localization of one or several red pimples, pimples are hard, the surface is smooth, there is obvious burning and pain, the pain will be obviously aggravated by pressure, usually 1-2 weeks will subside by itself. The pimples are fleshy skin color, no pain, no itch, consider epidermal cysts, this is the sebum secretion, poor drainage caused by the pimples smooth surface, hard texture, sometimes pushing the pimples can be moved under the skin, usually without any self-conscious symptoms. Some pregnant women may have scattered hard lumps on the areola, which are Montgomery’s nodes, caused by the vigorous activity of sebaceous glands during pregnancy, and they have no effect on the body and breastfeeding in the future, and some of the patients can subside on their own after the end of breastfeeding. Some newborns, especially female infants, will have a small lump on the nipple or areola, which is painless and itchy, and sometimes slightly enlarged after being heated, which is caused by high estrogen in the body, and it can also subside after a period of time.