Have totally killed my site dead. Can't even access dashboard.

Installed a few days ago (v3.5.1?). Please don’t laugh too had. Wanted to get fancy beyond my ability with the Clean Retina theme and remove the copyright in the footer. I created a child theme and added a functions.php file to add code as suggested (support/topic/clean-retina-theme-horse-footer) but it just removed all footer including Recent Posts widget. I created a new test page on the site and both the title and my test copy appeared on the page and in the footer. ? So I tried to delete all code in the functions file, still no change. So I copied all text in parent functions.php and pasted into child functions.php to see if it would just “reset.” Now no site, no login, no account in WordPress at all. Hosting tried to restore files from a few days ago, no luck at all. HOW DO I FIX this blasted mess. Thanks.