No, you will not have to re-register. At the very most all you should have to do is log in by entering your username and password that you already have.
I found another glitch tonight and have fixed it. there are a lot more little places to change the name than I had thought of. Hopefully, as each one is found, fewer problems will happen.
Once the old name is gone, all the problems should either go away completely or become glaringly apparent and therefore become easy to fix. Either way, it should all be fixed soon! Hang in there everyone!