The past cannot be cured. There is nothing that you can do now to “undo” what has already happened. You can (and should) sincerely apologize if you’ve wronged someone. But at some point, you need to let go of the past.
Focus on your next decision, on making the right decision, and go from there. That’s all you can do. If the other person accepts your apology, great. They are a forgiving person. Remember this when others wrong you…you should forgive them.
Forgiveness will set you free. Holding grudges will only keep you in a dark place.