My mom described the feeling as having little men with swords slashing in her mouth and throat. She was given meds all through her tx's. Her Ro had her on neurontin for nerve pain, oxycodone for pain, duragesic patch for nerve pain...she is still on all these meds, though the little men seem to have left finally!
I agree with everyone, push the docs. I also would push about the feeding tube, he can still eat by mouth and swallow through exercises and such.