I can feel worms in my mouth but can't see them, dentist treating for dry mouth, I can't cope with these feelings, been 4 months suffering now?

Need advice. Your problem may be as much psychologic as physiologic. Please consult with a competent mental health professional.
Not normal. If there were truly worms inside your mouth, you would be able to see them. Abnormal sensations are often caused by a neurologic or psychiatric problem, please see a psychiatrist for an examination. Be well.
Possibly neuro prob. It is probably a nerve problem, possibly even something in your brain going on. It is certainly abnormal and you should seek help. I have never heard of real worms in the mouth, but there are worms in the GI system, so you really need to be checked out throughtly. This can be something life threatening so do not ignore it. Get help. You are best off in a hospital where they can run all tests.