Find and Replace -- Undo-ing an accident

I was using the multi-file find and replace and was about to change the "email" to "e-mail", but while caught up in which files were affected I accidentally hit replace all before filling in the replace text box. Because it was left blank, it ended up deleting every use of the word "email" in my system (i.e. replacing it with nothing).

I had the Make Backups box checked, so presumably backups were made. How do I restore those backups?