How painful is nose cauterization?

Not bad: It dependson what is needed. If the area on the septum is small, without a real "juicy" blood vessel, i spray the nose with Lidocaine and afrin, (oxymetazoline) and then put little pieces of cotton (cottonoids) with the same med in the nose for 10 minutes. This numbs pretty well. If I have to use electrical cautery, I do this and then inject local. This smarts a little. Then the cautery rarely hurts.

Depends: Nose cauterisation is not pleasant but most doctors spray local anaesthetic before cauterisation and that helps to decrease the pain.