I'd say to get another vet to look at Dusty. Daisy has a growth on her neck that I freaked out over, and it sounds just like Dusty's. We got her checked out and they said it was just a fatty cyst and unless it gets bigger or attaches to something, we can just leave it. You can read the posts there... it's under "Bump!?" under Dog Health. Good luck!! I know it's scary.