I have a dentist appointment next week. I hate going to the dentist. I don't want to go.
I went through that for like 5 years.  Ended up finally going and they've made a lot of advances in comfort since I last went before that.
I have a tooth that has been bothering me and I've already put this off for so long.
Yeah, you should definitely bite the bullet (metaphorically).  It'll only get worse from here if you don't do anything, and it probably won't be as bad as you worry.