This page should help you backup your database:
http://help.godaddy.com/topic/67/article/5648
I'm guessing that process will put a file on your server that you can download to keep it safe. When you hit edit you may be able to actually edit records. I have no idea what godaddy actually lets you do. Their live chat support will likely be able to tell you how to edit a database manually, though they wont help you troubleshoot this kind of software (at least not for free).
Another option would be to find a mysql database editor. I have used one called Toad in the past and it seemed to work pretty well.
My team uses a phpbb board to communicate and I have had my fair share of experiences like this when updating/customizing. I ALWAYS download the entire installation directory AND backup the database before doing any work (after the first time I broke it, at least). That way if I'm completely screwed, I can just re-upload everything.