Always best to copy over what files you will be modifying into the child theme first, then make your changes there. I know a few who have done it similar to what you have done by making the changes in the parent theme, then porting it over, only to discover something was missed.
I’m understanding that you need to revert back to a previous version? If you have a theme membership, you can go to the downloads area and download the previous version(s). If you just have the individual purchased theme, I can send you the version you need…do you remember what it was?