We don't currently have a way to revert back to specific versions of your site, unfortunately. We can restore fully deleted pages if you deleted a page, but we can't restore content or revert it to previous versions.
Since your published website still has the content, you can copy text from there and right-click and download images as well, that way you can use that to recreate your content as it was before you made changes.
One additional note about an undo button. We don't currently have that for the classic Weebly drag and drop editor, though we do have an undo button for the newer Square Online editor. That button will undo changes you've made while you keep the editor open (once you exit the editor, close your browser tab, or go to another site that undo history is lost).
While we don't have a way to convert a site from one editor to another, you can try out the Square Online editor by signing up for a new account and choosing the option that you want to sell online.
