Tell your supervisor and offer to pay to repair the damages. What’s done is done, and you can’t undo it. Chances, are, they’ll accept your offer to repair the damages and be done with it. It’s better than feeling guilty, and if your supervisor happens to find out you’ll most likely be punished further, and your chances of getting fired will go up. It’s most likely not the first time this has happened and you most likely will not get fired if you just tell the truth and offer to do what you can to fix it.