I hope the canker sore is going away and you are doing better now. I have had the thought that perhaps there is an imbalance of your good bacteria. I have heard that in China they pay special regard to this. You could try some yogurt pills in capsules and even open them in your mouth and letting the good bacteria stay there. We are pulling out the good along with the bad.
My email is down so I won't know if I get any replies but I'll try and check back. I do hope you are doing alright. I'm praying for you...c