Illness related to mouth and lower body sores?

My boyfriend always have sores inside his mouth and on his lower body. The ones in his mouth look resembling ulcers, however he get them in mass quantites (almost 30 at a time) and they reach from the size of a pinpoint to the size of a dime. He gets them adjectives over the mouth (tounge, gums, throat, roof, etc). He also gets sores on his lower body (stomach, dribble away, thighs and butt). They look like red friendly sores and are about the size of the diameter of a pencil. He say that the sores on his body are painful, but are zilch compared to his mouth. It affects his eating behaviour and speech because it is so painful. There are times when he scarcely eats and doesn't speak for days because he is contained by so much pain. He have been to the dentist several times for laser treatment for his mouth, which works, but solely temporarily. Also, he said it seems to own gotten worse with age. They started when he be about 13- he is presently 21. He says very soon it is the worst it has ever be. Any ideas or suggestions? THANK YOU he must see dermatologist for presently he should care of cleaning them and donot use slimy ointment or cortisone containing one and run vitA b1 b6 and b12
See a dermatologist. Auto-immune lichen planus?