You can always view a complete history of edits to pages in your Canvas course. To revert a page to its previous version, simply click the date and time of the page version to restore. 

Read more on Canvas Community:

 

If your page has been deleted, you can try restoring it by accessing the list of deleted items from your Canvas course:

  1. Enter your course URL in the web address bar and add “/undelete” to the end of the link- e.g. https://auckland.instructure.com/courses/16708/undelete
  2. Locate and select the page and click the restore button.