Hi Christopher,
If you append /default.aspx?ctl=Login to the and of the sites domain, you should be able to force the default dnn login to come up and then you would be able to login and change things back to normal.
If that doesn't work, you may need a more drastic measure which would be to do it on the database directly. But that is a bit risky and without seeing your situation it would be hard to advice. Is my suggestion above doesn't work, just drop me a private email (aderson at dnnhero dot com) with FTP access to the site and I will give you a hand.
Cheers,
Aderson