Well that's a bummer... though I can think of one way to circumvent that.
You could ask someone to movechar so that the rename timelimit goes away.
Or, like I once did myself.
A simple way of doing it, is since you have no account and it's empty. You could start FL without launchpad and see if your char is still there. If it is, then good. You can put a movechar code on it, then use that new account you made and transfer it to it. Then you should be able to rename it again.
If not.. well that's a bigger problem.
Just try to see if you can find your char by launching FL without launchpad.