My son had his nose cauterized 2 years ago. The past two days he has had about a dozen severe nose bleeds. Does cauterization stop working?

Did its job. Cauterization is not forever it is for today & maybe this week.The nasal membranes re-establish the tiny capillary network within days/weeks to add moisture to the air we breathe so our lungs don't get too dried out by dry air.Your kid has issues with irritants or allergies that should be addressed long term.For now, get in and stop the bleeding for today.
The Nose Knows. Yes, it "stops" working because the nose heals, which means the cautery has its job. But it can work again if the bleeding is from the same problem. A dozen "severe" nosebleeds does not sound like fun and can get messy and even lead to dizzy/fainting problems if they are too big. So, it's near time to go get that nose checked and see if something will be necessary to quell those bleeds.
Probably. developed new blood vessels , ( vascular plexus ) go back to the doctor , don't allow to have ' dozen severe nose bleeds ' Cauterization is a simple safe procedure and don't worry.