mary
                    
                    
                    
                    
                    
                    
                    
                        
                        
                        My teenage son also suffers from cancer sores inside the mouth.  They could be brought on by stress, ice, and other traumas to the inside of of the mouth.  He uses lysine pills - found at your drug store with the vitamins. He will take them when he knows hewill be under stress.  They seem to help.