404 error after login

This is a self-induced but I am uncertain how to fix it.

I originally created my website with Frontpage, later installing WordPress in the folder wpblog.

When I went live with the WordPress site I put a redirect onto my original index.html page to the wpblog folder. This worked for quite some time but today I felt the need to change my WordPress settings and now I get a 404 error after trying to login. I also lost all formatting to the website.

On my site’s dashboard on the left hand side I clicked on Settings, then General. I changed the third and fourth field from mysite/wpblog/ to plain ol’ mysite/. I did this because I thought it would overwrite the index file with the redirect but that didn’t happen.

What file do I need to edit through FTP to be able change the directory back to the wpblog folder? I looked in the wp-config.php file but I was uncertain what to change and thought it best to wait before doing any more damage.

The website address is https://www.modernjediknight.com if that helps.