Hi.
Itch doesn't have any version management system built in. All changes are final. The admin has said that if you delete a page, it might be possible to recover it if you contact support, but if you edit it, I think it will be impossible.
You can try to contact support directly, but I see that as unnecessary, support has quite a few tickets to deal with every day and it's unlikely that they'll answer you quickly and even less likely that they'll be able to recover a previous version.
Personally, I think the quickest way would be to edit the page again.
EDIT:
Sorry "No time to play" I see you answered while I was writing.