What could be causing my chronic nosebleeds and what should I do about it?

Okay, so I have chronic nosebleeds. They happen once or twice a day and they last a good 10 to 20 minutes. I went to an ENT before and they cauterized my nose. They said the cause was that I had extra blood vessels and that I should have been having a nosebleed every time my pulse went up my entire life. Apparently extra blood vessels in your nose is a birth defect. But, anyway, I got it cauterized, but a year later, my nosebleeds started happening again and they've been just as bad as before. I've been dealing with it for a long time since then now. So, I'm starting to wonder if the ENT was wrong. Could they be caused by something else? I'm pretty sure it's not dryness or temperature changes, and the nosebleeds starting happening around the same time I developed Melanoma. Could it have anything to with that? I didn't have them my whole life like the doctors said I should have. So, I'm just wondering if anyone knows anything about this type of thing.