I WAS LOOKING FOR SOME ONE WHO KNOWS ABOUT MOUTN

I WAS LOOKING FOR SOME ONE WHO KNOWS ABOUT MOUTN PAIN FOR MY BROTHER. HE HAS SUFFERED WITH SEVERE MOUTH PAIN THAT SHOOTS DOWN TO HIS FOOT WHEN HE EATS. HE HAS BEEN TO SEVERAL DIFFERENT KINDS OF DOCTORS BUT THEY CANT FIND ANY THING. HE SAYS HE CAN FEEL A STRING LIKE IN HIS MOUTH WITH HIS FINGERS BUT THE DOCTORS CANT FIND IT WITH THERE HANDS CAUSE THEY HAVE TO WEAR GLOVES. DO YOU KNOW WHAT IT COULD BE>