Liquid nitrogen, i.e. liquid nitrogen, is a form of liquid nitrogen at minus 196 degrees, which is more widely used in clinical practice. If the candidate is a pigmentation with thin superficial stratum corneum, such as seborrheic keratosis, liquid nitrogen freezing can be used to remove the pigmentation. However, for pigmentation in the dermis, liquid nitrogen is seldom used to remove it. Liquid nitrogen freezing has certain risks, as follows: 1. Although short-term spot removal by liquid nitrogen freezing has a certain effect on spot removal, it has a certain chance of recurrence and will cause secondary pigmentation, and after half a month or so, after the flaking of the spot area is removed, it is easy to leave pigmentation, commonly known as “anti-black”. In this case, the pigmentation may be more serious; 2, freezing is operated from the epidermis, and it needs to be deep to the dermis to have effect. If the care is not proper, scars may appear. If you want to get rid of blemishes, it is recommended that you go to the hospital and let the doctor diagnose the site and type of blemishes to determine what kind of blemish removal method you should use.