The first thing to do would be to look into hyperbaric O2 treatments which may get this to heal up. As your doctor for a referral to a facility that does this. I am surprised that your doctors have not considered this avenue to pursue, as it is commonly used in cases of slow healing. Looks like you have already done this once for another healing issue, so this should be something you are familiar with. Non healing wounds are common in patients that have had radiation, as the micro vascularization in the bone has been damaged or destroyed by the radiation treatments. Is this an oral surgeon that understands and works with people in oncology and radiated patients as a matter of routine?

Also please keep all your posts related to your own issues in one forum and one thread for now. It is hard to follow your issues for people if they are in multiple forums.