Exact same thing happened to me with my GCC today. I was scared to death. Looked like a bad bruise or blood, and I didn't know what was underneath it. I almost went to the vet, but I'm sooooo broke right now I went to a friend with lots of experience. Birdie is not terribly hand friendly. She was eating ok though and poops looked ok too. My friends started relaxing her by grooming the pinnies, and eventually came to the conclusion that she itched herself so bad she scratched, and caused blood to pool and dry on her beak. They still felt it was not necessary to go to the vet. They didn't want to ruin the positive handling that occurred, but we finally decided to at least try to clean it up. It was a cherry skin. Felt pretty silly. But I do know the beak is in a way like a toenail, and regenerates itself. If the bird seems ok, I think I'd just keep an eye on it.