Okay, I got it fixed. Another thread reported that a change in the login setup to prevent hackers was causing this problem. I read the following…
“I discovered my WP was upgraded automatically to 3.8.2. I was using a child of a theme that was out of date. Didnt notice the parent theme had a new version release.
WP 3.8.2 addresses a hack problem with forged authentication cookies that stop you from logging in. You must be running a version of your theme that is not up to date and is not compatible with 3.8.2. (the timing of this is too coincidental) I think that’s how the hack enters.
My host logged in for me using another password then deactivated my theme and activated the WP default theme (twenty eleven).
Was able to login after that. Have reverted to my parent theme and upgraded it then activated it. It’s okay now. “
So…
1. Went into phpMyAdmin and changed my login password (see https://codex.www.ads-software.com/Resetting_Your_Password )
2. Logged in, but found my dashboard broken up with no CSS, but was able to find the Appearance > Themes area and selected my parent theme, getting out of my child theme.
3. Then I kinda got lucky because my email notifications told me all of a sudden that one of my sites had automatically update to 3.8.3. Ah, a upgrade. That would update the database and “reset” everything.
That took care of everything. One other person said they downgraded to 3.8.1 and then ran the updater to get back up to 3.8.2. Same idea.