Angular cheilitis, an early sign of riboflavin deficiency, is a manifestation of impaired cellular energy metabolism and oxidative damage. As the deficiency worsens, redness and cracking spreads from the corners of your mouth to the entire lip margin. The mucous membranes of your mouth, tongue and throat become reddened and tender, and you develop an oily scaly rash on your face, eyelids, ears and groin area. According to "The Merck Manual of Diagnosis and Therapy," you may develop neovascularization, or growth of abnormal blood vessels, over the surface of your corneas, leading to visual problems. Anemia may occur as the result of reduced red blood cell formation.