Tom, have you considered having more HBO? Sometimes it takes more than 21 to heal. The first time I did HBO, my doc kept extending my treatments. I was making progress but very slowly. I think it took me 60 dives before I healed from the surgery for my 2nd round of oral cancer.
Everyone is different with this. I struggled while Ive seen others sail right thru it. A mandibulectomy is a major surgery. It is very delicate with the surgeon connecting teeny tiny blood vessels. I hope you carefully consider all your options. If it were me, I would try more HBO hoping that would help the jaw. If you put off the surgery your jaw will only be in worse shape and harder to fix.
Here is a link that details what I went thru. Just remember not everyone goes thru such difficulties. It was the 3rd time I had cancer in 3 years so my body was not strong going into it.
ChristineB's mandibulectomy