Forehead wrinkles are a natural part of the aging process, appearing as thin, vertical lines or wrinkles on the surface of the forehead. In addition to skin aging, forehead wrinkles can also be caused by repetitive facial expressions, sun exposure, smoking, stress, and other factors. When expressing emotions, facial muscles can constantly contract and stretch the skin, which eventually leads to the formation of forehead wrinkles. HOW DOES AGE AFFECT...