Skin mucosa generally refers to a protective structure covering the surface of the skin, such as oral mucosa, eyelid mucosa, nasal mucosa, urethral mucosa, etc. The main functions of skin mucosa for human body are barrier function, absorption function, secretion and diarrhea function, metabolic function, sensory function, thermoregulation function, etc., which help to maintain the normal physiological role of the body and organs, ensure the normal water content in the body, and at the same time can sense external stimuli, such as cold, heat, pain, etc. One of the most important functions of the skin mucosa is the barrier function, which can function as an immunologically active organ, that is, in the human skin immune system, the immune function of the skin plays an important role as the first line of defense against external viruses, bacteria and other antigenic substances, and to a certain extent, can protect the human body from the invasion of bacteria, viruses and other substances. Therefore, we should pay attention to protect the skin mucosa in our daily life, try to use soft-bristled toothbrush and gentle action when brushing teeth, and do not use sharp tools or sharp objects to contact the skin mucosa to avoid unnecessary damage.