I’ve always heard, “Never look back.” Just because there are things you want to forget and never go back to, you must not forget those things (good or bad) are the reason for you successes today.
The mistakes you’ve made are just as responsible as your good decisions for who you are now. Learning the hard way is something to be proud of, not to be ashamed of. Your memories do not come back to haunt you. They are just a reminder of how hard you worked.