Hi..
Thanks for the query..
From your explanation it looks like a severe case of
Burning Mouth Syndrome and as you are diabetic, it can be a cause for it..
Other causes can be
dry mouth, deficiency of Vitamin B 12, stress,
acid reflux, side effects of medicines [if you take any] etc..
So first of all you should consult an Oral Physician and get a thorough clinical examination done so that the underlying cause can be ruled out, this is because burning mouth is a symptom due to any underlying problem..
As of now you can gargle with numbing mouthwash containing
Lidocaine to relieve burning sensation..
You can take anti inflammatory painkillers like
Ibuprofen..
Start taking multivitamins daily..
The Physician can advise you anti depressants as they are helpful in relieving such symptoms when other remedies does not work..
Hope this helps..
Regards..