Hi there ~
I understand your concerns. Meth
usage has been associated with a lot of neurological symptoms and I am not surprised that you have the burning sensation on tongue, ulcers below your tongue and have pain on eating or doing anything with your mouth. The cure for this condition is to quit meth usage. I also thing that you should visit with a psychiatrist
who is a substance use disorders specialist, since I believe you are dependent on the meth and have become fatally abusive of the substance. I hope you do so as soon as possible to get an answer or solution to all your problems.
I hope this helps. Take care and have a lovely day!