I switched to this pool 24 hours ago and just realized I had my all my worker usernames in the wrong format, using a period instead of underscore. As a result, my BTC earned didn't go up at all even though I could see my hashrate

. Is there any way I can get the BTC credited to my account?
I would email poolwaffle or PM him here or on Reddit. Not sure, but maybe there's something he can do for you.
It's not just wallet address with any password?
You can use anything for the password. But you can also use different workers by using your bitcoin address followed by an underscore followed by a workername. This way each worker can have a different vardiff.
It's not required though right? I don't need to have it like that, or do I have to have at least something in there, like WALLETADDRESS_Something?