Hi I have a 4yr old male American Bulldog,...my dog somehow severely cut the under back portion of his tongue?

Hi I have a 4yr old male American Bulldog,...my dog somehow severely cut the under back portion of his tongue and had to undergo surgery to get it stitched up. However, the wound keeps opening up, have already had to take him trice to the vet for surgery. I've changed his food to soft food to aid him but because he keeps licking himself so the wound is not healing and I keep finding blood on his paws and spots on the floor every other day. The vet has prescribed antibiotics and some tablets to stop any itching but he still continues to bleed and has lost a lot of weight from 56kgs down to 39kgs. I cannot afford to take him to the vet so often and fear I may loose him. Any advise/suggestions would be greatly appreciated.