Oh dear! I'm so sorry....especially when they start using nasty words like "growth". It's like deja vue when Bacca's mouth swelled up for no apparent reason and they started talking about lymphoma. Yep, you start thinking the worse. They treated him first with antibiotics which seemed to do the trick - for a while - and then he was up and down all summer long. I would think he was back to normal, and then he'd be off his food again. Only to find out months and months later, that he seems to be hypothyroid (a good outcome, given the choices).
I don't know much about nose bleeds in dogs....is it like people, who get nosebleeds when its "dry" and the nose lining gets irritated? If so, it may never recur or it may now become a chronic condition relating to dry air, or the worst scenarios.
I would be inclined not to wait...given my own procrastination, I wouldn't wait so long again.