Honesty is the Best Policy
One of the things that I have learned in my long and varied life (OK, it hasn’t been that long or varied, but go with it) is that it is basically always best to confess and apologize immediately when you’ve done something you shouldn’t have. If you do this, people tend to be more understanding and forgiving because you did not add lying and secrecy to the list of bad things you did.

On the other hand, if you try to lie and keep it a secret, not only is there a chance that karma is going to come around and punch you in the face in the form of a major car accident, but you also might convince your coworker to force you to pay for damages to their car.