If it were me I would not say anything to anyone. Confessing to every thing you've done wrong just brings a lot of negative attention your way. If they ask about it you're probably best to admit it but only because they will probably have some evidence already and there's no point in denying it. If they find out I would claim ignorance and say I didn't know it was wrong.
This is just what I would do if I was in a similar situation.
This is just what I would do if I was in a similar situation.