Hi im not a vet or anything just some info i have learned have you increased the heat and humidity in the snakes tank/tub this will usually help them heal. These steps may help put them over the edge of healing. What type of heat source are you using and and type of enclosure would help us understand there environment. This is important in understanding there situation. If you are willing to keep fighting then keep fighting i wouldn't give up till my snake died but that is just me. Good luck