i have had mouth ulcers for months now
i think it is due to the medication i have restarted since over a year ago (lyrica) and ( synthroid ) since March this year
i have been back & forth with the immune dr and my system is fine
i stopped the lyrica and the mouth ulcers still show up but not as severe as they were (just placed a call to the neurologist) about my meds but if you look up the meds i mention they say they are know to cause ulcers in the mouth (dry mouth)
also stop and read to see if SLS is in your toothpaste - do not use listerine
the ent dr. (nose,ears,throat) doctor told me no good for mouth / ulcers
i use perioxide & warm salt water to gargle and buy special mouthwash (CLOSYS) & toothpaste at the drugstore with no SLS in it (sodium lauryl sulfate) NO ALCOHOL you can also get a q-tip and place perioxide onto the sore to help it heal quicker (Good Luck!) I know they hurt.