I had lots of problems with mouth ulcers in my teenage years. My doctor prescribed a sort of paste which completely sealed over the sensitive area of the ulcer, which worked really well.
I later purchased the same stuff without prescription, so I suspect that any pharmacist would still be able to supply it (even though I can't remember the name of it). However (through TV advertising) I've recently seen that Bonjela seems to have started marketing a very similar product,so perhaps it's worth a try?
http://www.mouth-ulce...mplete_plus/index.php
Chris
Chris