IF YES: Then there's really nothing to regret. You wouldn't be who you are or where you are if you hadn't made that decision that seems so irrelevant to the bigger picture.You've done stuff and stuff has been done to you, but at the end of the day you will learn or learned something from that embarrassing experience. Also, you might not regret it but actually just feel EXTREMELY embarrassed. You don't wish you didn't do it because you wouldn't have known how terrible that idea was if you didn't follow through. Some people (I included) learn from experience, and no matter how often someone tells you not to do something you still just have to do it to get a real grasp of the situation.
IF NO: You don't regret the decision, you just don't like how it impacted you or the people around you. There's no turning back time. Own up to it and try to understand why it is that you feel so terrible. Again, it's highly likely you're super embarrassed but you are your biggest critic. No one is as mad at you as you are so forgive yourself and allow yourself to grow from that experience.
IF THIS WAS SOMETHING THAT HARMED YOU OR SOMEONE ELSE: First, regret is definitely a step towards fixing your moral compass cause wtf! Anyways, you now know it's wrong and have to suffer the consequences of your actions (as small as they may be). If you regret it, DON'T DO IT AGAIN. Your mind knows it was messed up. You know it was messed up. Walk away from that mistake and never make it again. Live with the pain you've inflicted and spend your lifetime trying to forgive yourself and asking for forgiveness (if possible).
