If you really want your memories erased there is one way that doctors have found to erase your memory but I would not recommend it.
The way that doctors say you can erase your memory quickly is through electroshock therapy.
Or you can go an easier and less painful route by trying to create some new memories and think about happy things if you're trying to forget about bad things that have happened to you.
There's also another way through use of blood pressure pills to help you erase your memory and forget things but only do so under a doctors advise.
The best thing you can do though to erase your memory is to try and replace those bad thoughts with new thoughts and try not to think about the bad things.
And in time maybe a year or so you might forget about those bad things that happened.