Suggest Treatment For Canker Sores On The Tongue

Question: I have been getting canker sores non-stop for the past year(only they go away when i take steroids for my back). I now have chapped and very itchy lips and chin that wont go away(again, gets better with steroids and then comes back). My MD says its stress, but ive been much more stressed in my life and rarely had a canker sore. Could something else be going on?it has been going on for more than three weeks, for a year in fact(as previously said). I take a B vitamin as well as multivitamin. It cannot be a vitamin deficiency. I doubt they are due to a tooth because they happen all over my mouth and tounge. Again, my doctor says I get them because of stress, but I am confused because I have had stress on my life and they are suddenly showing up. They get very large and painful and when they finally go away a week or two ago by and then another one errupts It is very frustrating. I was just hoping for a possible cause of that I could make them go away. Steroids to help but obviously I can't take them every day. Let me know if you have any other ideas.