I am experiencing unable to open mouth (jaw), diarrhea (quality: severe) and rash on back. the following also describe me: frequent stools, rash, weak immune system, and abdominal spasm. what should i do?

Various symptoms: I'm unsure that one disease process can explain these varied symptoms. I would start by seeing a physician who will take a thorough history and system review, perform a complete physical examination and order appropriate tests in order to make a diagnosis. Referral to specialist like dermatologist,oral surgeon and gastroenterologist will probably be recommended,also.