what causes a dry spot on lip
Certain factors can exacerbate the patches of dry skin that develop around your mouth. This includes frequently licking your lips, according to NetDoctor. If you live in a cold climate, cold weather can dry the skin, causing patches to develop on the lips.
Also termed solar cheilosis, this condition is the result of chronic over-exposure to ultraviolet radiation in sunlight. It usually occurs on the lower lip, which is dry, scaling, and wrinkled grey-white in appearance. It is especially common in people with light skin types who live in sunny climates (e.g. , Australians of European ancestry), and in persons who spend a lot of time outdoors.