I agree with all of the posters above. After my radiation TX, my wisdom tooth cracked. My prosthodontist tracked down a root canal specialist (an endodontist) who used the dental version of "robotic surgery". My prosthodontist had to intervene to stress that I should NOT have an extraction due to risk of ORN which he deemed unacceptable. Believe Christine when she tells you about the horrors of ORN
Your oncology doctor should have recommendations for dentists with cancer experience or be able to get an intro to the oral medicine specialist that Brian mentioned- don't delay - start calling and get this fixed.
Charm