Bill

You’ll need to replace the edited one on your hosting account server with a fresh, unedited one. You can use an FTP client (like FileZilla), or your web-host’s cPanel or file manager to do this. File manager is easiest if you aren’t familiar with ftp.

Find a copy of it in a freshly-downloaded copy of the theme. Copy the bad one from the server to your computer for reference, delete it from the server, and upload the new one.

Whenever you want to make any changes to your theme, you should make them to a child theme instead. That way you won’t lose your changes when the parent theme gets updated. A child theme is not difficult to make and can save you a lot of trouble in the future.

Great! Glad you worked it out. Please mark this as resolved if you don’t mind.

I’ll assume you don’t have a WP.com account since you didn’t reply to that part of my response.

Since you seem reluctant to get into a technical approach (which is completely fine and understandable), I would recommend first contacting your web host to see if they can help you sort this out. The have all the access they need to look into this for you. If they are unwilling, we can move on from there, which will require you logging in to your hosting account and accessing files directly. Hoping your web host can help, but let us know.

Not to worry 🙂 There aren’t any ‘upgrades’ here on wp.org. Is your site perhaps a free one hosted by wordpress.com? If so, they may be able to help:
https://en.support.wordpress.com/

Otherwise, if you have the new password, try clearing your browser cache (probably in the preference settings of the browser) and your cookies (same place). Then try your new password again.

Have you been using a plugin to set up that alternative login address? If so, try disabling the plugin and logging in via the WP default login.

If you are unable to get to your admin pages, you can use an FTP client (like FileZilla), or your web-host’s cPanel or file manager to do this. File manager is easiest if this is new to you. Navigate to wp-contents/plugins, find the specific plugin’s folder and rename it (add ‘-hold’) to temporarily disable it.

You didn’t mention updating your name servers or transferring your domain. Until that happens, and time is given for the changes to propagate, the domain will continue to resolve to the old site.

See: https://en.support.wordpress.com/moving-to-a-self-hosted-wordpress-site/

and especially: https://en.support.wordpress.com/moving-to-a-self-hosted-wordpress-site/6/

Please don’t create duplicate threads for the same issue. We know it’s frustrating, but a little patience please. 🙂
Continue here if you would:
https://wordpress.org/support/topic/cant-login-153?replies=2

Help for your commercial theme seems to be here:
http://styledthemes.com/index.php?option=com_content&view=article&id=182&Itemid=205
I’m afraid we’re only able to help with themes found in the WP repository. Good luck!