A severe deficiency in vitamin B12 can manifest through several distinct dermatological and facial signs. Common indicators include angular cheilitis (painful cracking, dryness, or inflammation at the corners of the mouth), glossitis (a smooth, red, swollen, or sore tongue), and facial pallor or yellowish skin undertones resulting from megaloblastic anemia. Patients may also experience premature graying of facial hair or chronic skin hyperpigmentation in severe, prolonged deficiency states.