My Husband Has A Callus On His Pointer Finger On

My husband has a callus on his pointer finger on the palm side of the hand .....it is HUUUUGE.......He had it cut off at a clinic one time.....and it just grew right back, it also causes him much pain. Is this a condition? Does he have maybe a splinter stuck in there that is trying to come out? It sticks up almost a half of an inch off of his hand.