I had a lot of cancer sores as well. I had them on my tingue and on the back of my throat. My friend told me that they usually appear on people that smoke. I used to be a frequent smoker till I quit like 4 months ago. I went to see mt doctor about them and he said that they should go by themselves and that i should use mouth wash a lot and not eat as much as i used to. Till now the canker sores have gone and my throat isn't as irritated as it use dto be but theres still some that r still there. What should i do? If u know anything that might help me then please reply back to this message.