Mucous Membrane Pemphigoid is a rare autoimmune disease where the immune system attacks the "basement" layer of skin.. causing blisters to appear, break and then scar over. This can occur in your mouth, nasal passage, throat, skin, genitals, anus, and eyes. - it is incurable and painful. Most often treated with steroids which have harsh side effects that will effect your daily life. It is survivable but needs more research and treatment discoveries.