Page custom CSS deleted when restoring an autosave

I am using xthemes version 2.4.0. While editing a page on wordpress, I got a prompt that there was a more recent autosaved version of the page available. When I reviewed the autosaved page, it seemed to have a few changes I had made that weren’t reflected in the version I was working in so I restored the autosaved version. As soon as a restored the autosaved version, all custom css for the page was deleted. I tried restoring previous versions of the page and no matter what version I restored, the css was no longer there. Given the extensive amount of custom css I had entered in the page, I am moderately devastated. Is there any way to retrieve the custom css? I’m not sure if this is a theme issue or wordpress issue so I’m asking in both places. Any ideas on getting my custom css back would be greatly appreciated.