My ds broke his wrist in a Saturday. It was X rayed and put in a temporary cast that night, and he was then given an appointment for he fracture clinic on, I think the following Thursday. I queried the delay, but was told that it wasn't any use going sooner because the swelling had to go down a bit before it could be x rayed again and a permanent cast put on. We were told to go back to A and E at once if he was in a lot of pain, or if his fingers swelled up.
Maybe your dd is the same?