Life is a straight line. We can never undo what has been done. We can, though, learn from our past. We can learn what went well and what didn't. We can apply that learning to our future to make our lives and the lives of those around us better.
Too often, we, both as individuals and a society, try to forget the past and pretend that it never existed. When that happens, what is the next step? As the old saying goes: "Those who forget the past are condemned to repeat it"
(George Santayana).
Remember the past. Ask yourself "What can I learn from that experience?" Learn it and make your life better because of all of your past experiences. Remember, also, no two individuals have had or ever will have a life of identical experiences. Use them to be the best unique you that you can be.