I tried adding the following to my functions.php of my custom theme...
How did you do that? Using that same method to again access that file, or using either FileZilla or the BlueHost cPanel File Manager, go to what is likely /public_html/wp-content/themes/ and find the folder for whatever theme has the functions.php you had edited and replace that edited file with an original.
If that does not work, go to what is likely /public_html/wp-content/themes/ and re-name the folder of the theme you had been running to deactivate it and then WordPress should automatically activate a default WordPress Twenty-Something theme if there is one there. After that, you can even delete and replace the entire theme you had been running by re-uploading it or any other theme right there into what is likely /public_html/wp-content/themes/ and WordPress will show it available at your Dashboard after your next browser refresh there.