Fixed. The vandal hasn't made any more edits so there is no need to block them from editing. Help:Reverting has a brief explanation on how to revert an edit, and I wrote a better help article here detailing the same thing.
It's possible to revert multiple edits. All you have to do is go to the page history, click on the timestamp of the revision you want to restore, click on "Edit", and then just hit "Publish" without making any changes. That should restore the page to that version of the page.