Is it normal to go back in time in your mind?

a wise man said " its not what goes into a man's mouth that can harm him but what comes out"

Doing that is natural and it can be helpful in learning how to handle situations better.

However, it's not positive or helpful to get obsessed with reliving a conversation or confrontation you feel you could have handled better. What's done is done. If you feel remorse for something you said, the best thing to do it apologise. It might not be accepted, but that's the other person's choice, and you will have done all you can to make things better. If you feel you should have been more assertive in how you responded to a situation, often all you can do about that is resolve to do better the next time something similar happens.

Reflection is fine, regret without action is useless.

Often I will think of a conversation and think Damn I should have said this or that instead of what I said. The guy that said hindsight is 20/20 was right.

Ikr, life is full of regrets sometimes, wish it was possible to change some part of my past....

Its what happens when your brain is showing you what to do if you encountered a situation like that again.