Cheilitis is not a skin disease; it is a disease of the oral mucosa and falls under the category of oral mucosal diseases. Cheilitis is a mucosal disease characterized mainly by dryness, cracking, and scaling of the lips. Its types include dry scaling cheilitis, allergic cheilitis, benign lymphoproliferative cheilitis, granulomatous cheilitis, glandular cheilitis, fungal cheilitis, and photosensitive cheilitis. The onset of cheilitis is greatly related to long-term irritation and poor lifestyle habits. Seasonal changes and dry weather also increase the incidence rate, and windy conditions can easily lead to dryness and flaking. Cheilitis is also related to sun exposure, which can cause erosion of the upper and lower lips, known as actinic cheilitis. Patients with actinic cheilitis should first focus on avoiding light, reducing outdoor activities, and protecting their lips.