You can't undo what you have already done, namely and most particularly to yourself. Flashbacks can happen, days, months and or years after the fact. And when they do, hey lookout. I am speaking from experience. Now, many years later, since my last ride, I had one, a flashback. It was not what I expected, nor was it like it was back in the day. I talked to a friend about it and they are certain that I've reverted back to the days of yester year. Friendships are fragile.