This is called nipple depression. Because nipple invagination becomes more and more obvious with the development of adolescent breasts, the treatment of nipple invagination usually starts from 18 years old. Before treatment, we should first judge the degree of nipple invagination, put two fingers around the areola, so that the nipple protrudes to the surface and squeezes to the middle. If the nipple can be squeezed out and can stay for several seconds, the application of negative pressure suction can correct the invagination deformity. For young women in the process of puberty, physical therapy can be effective, and self-treatment is the first choice. 1. Hand traction: squeeze the nipple out of the skin surface by yourself, hold the nipple horizontally or vertically with your thumb and forefinger, and continuously or intermittently pull the nipple outward for about 30 minutes at a time, alternating sides. Mild nipple invagination can be treated by itself first. Wash with warm water twice a day, and then gently pull the inverted nipple outward. Don't pull too hard to avoid damaging the nipple. You can also gently pull out when you wipe your nipple in the shower, and pull it repeatedly to make the nipple protrude. If you can't pull it out, you can put your thumb on both sides of the nipple and push it back and forth hard, three times a day, five times each time. 2. Instrument traction: that is, using the principle of negative pressure, the nipple can be sucked out by manual or electric breast pump, which can suck out the nipple continuously or intermittently for 30 minutes each time, alternately on both sides, 3-5 times a day. After two months, the above two correction methods can get good results. 3. Continuous negative pressure suction method: syringes of disposable syringes, continuous negative pressure suction devices sold in the market, and negative pressure balls for sucking milk can also be used. After sucking out the nipple, keep 1.5 ~ 20 minutes, several times a day, and stick to it. Those who are ineffective for more than 3 months generally need surgery. After marriage, the man can suck his wife's inverted nipple. This kind of sucking can not only correct nipple invagination, but also prevent mammary gland inflammation, and of course make husband and wife's sexual life more harmonious. At present, there is a "nipple lifter" on the market, the principle is similar to the later one, but it can be fixed for a longer time and can be worn for life and work. When using enhancer, start to inhale 1 ~ 2 times a day for half an hour each time. If there is no reaction, the adsorption time can be increased. Generally, you can suck out the nipple in about 30 days, and then consolidate the treatment for 2 ~ 3 months.