The nipples suddenly become hard for a variety of reasons, the specific analysis is as follows: 1, nipple injuries, nipples are squeezed or impacted resulting in nipple congestion, redness, swelling, rupture, no wound can first ice, 48 hours after the hot compress and spray Yunnan Baiyao, if there is a wound need to stop bleeding, and then apply erythromycin ointment. 2, nipple stimulation, such as cold or fear after the nipple will be upright swelling pain, remove the stimulating factors will be