I don’t think you can forget it. You have to simply accept it and move on. I have done some jacked up stuff – to myself, mostly – that has drastically altered the course of my life. Regret used to rule me. It still rears its ugly head, but not nearly as much as before. I have no advice on how to let go other than to start making better choices and realize that getting on the right path from here on out is the best you can do.