Radiated bone doesn't always heal well after extractions, as the blood supply has been compromised. So hyperbaric dives will help that some. It doesn't work for everyone, but if you have the ability to use it, it may very well be worth it. I don't know where you got the idea that this could make you blind. It does mess with your vision a bit for about 30 days, but for me, and for everyone that I have talked to, that meant that my vision wasn't as sharp when it came to reading street signs down the road, it wasn't something that I really noticed much otherwise. In thirty days everything went back to normal and that was that.
As to what you mean by dead teeth, I'm not sure. But if a tooth was in good bone, and mostly intact you could always have a root canal done on it. Then it is dead for sure, as the root canal process takes out the pulp chamber and the nerves that feed the tooth and it becomes ankylosed into the bone. Endodonically treated teeth can be brittle, so you have to be careful with them afterwards but that is an option to pulling. Its about a thousand dollars a tooth for a root canal, and not a cheap idea. But I would have chosen that for myself if I could have, but the two teeth that I needed to have taken out were in bone that had ORN issues, so they were going to be lost anyway.
I don't know of any lung issues you think you mightt have unless you have some pre existing condition, which would make you not a candidate for HBO treatments. But getting more oxygen shouldn't hurt normal lungs. If anxiety is an issue for you, you could ask to have some meds to calm you before your first few dives, something like Valium (benzodiazepam) which is commonly used to treat anxiety. After you got used to the process, you probably wouldn't need to take them through the whole corse of dives.
Laying flat is very comfortable in there and the video to watch movies is right above you to look at, you will have a soft thin mattress to lay on and pillows. It's pretty comfortable, and getting engrossed in the movies that you get to pick will take your mind off of where you are. Before you know it the movie ends and the dive is over, till the next day..... I caught up on lots of great movies I had forgotten about.