Well, what happened in the past you cannot change. The best thing you can do is apologize for what you did and work with the people you hurt to prevent this sort of situation from happening again. I think if they see you apologizing and making an effort to change yourself, they may be willing to forgive you. If they do not want to forgive you, don't fret; you may have to "prove" yourself. However, if this is a repeated behavior, I'm not sure how they'll react to you apologizing, but I still think it's worth apologizing anyway.