Hi J4ck

I really feel for you. I had biopsy no 3 today.

My maxfac team disaprove of using anything on open sore areas. Their advice is holding preboiled warm salted water(I use salt flakes not table salt) in your mouth as many times a day as you need. It does have soothing qualities as well as healing.

I hope you get all healed up soon.xx

Boots own brand mouth ulcer gel contains a large amount of local anaesthetic. It is the best product I've found for topical pain relief in the mouth. It's very effective at killing the pain and the effects last for hours. 

I'm not sure if this would be contra-indicated in your case, but you could definitely discuss your options with the store pharmacist.