Mouth Cancer

in 2023 I got mouth cancer, was operated on, then had 34 treatments of radiation. In Oct of 24 I had a tooth out because Dr. said it was in the way. Then got covid. Then in Dec of 04 had second tooth out. They are now treating me for osteonecrosis and trismus. I am in relentless pain 24/7. I take acetaminophen 3000/day. Have had 2 biopsies which show no cancer, but mouth has ulcers. I am still being seen by my 2 surgeons. One suggested Botox and a hyperbaric chamber. I should add I also have MS for25+ yrs. Are these procedures safe for me? Does Botox spread? Thank-you.