I suffer sometimes with sores in my mouth due to my dentures and my denturologist recommended a product called, "Sterisol"
it works great. It is good for canker sores and sore throats also. It is a red liquid that you swosh(sp) around in your mouth.
I swear by this product and have recommended it to many of my friends. Within a day or two, my sores are gone.

It is sold in Pharmacy's, but I don't know if you can get it in the states or not. Look for it and let me know if you can get it or not okay.