Depends.......you just have to consider the pros and
cons.....
I think you should take into account the greater good of you
yourself and also of other people.
You need to consider your own's welfare and wellbeing also.
By thinking about revenge, dont you think you are being consumed
by hatred ?
Why not just let it go.
Imagine all that energy and all that emotion being put into
positive and constructive aspects of your life instead. Why care so
much about that other person and being so fixated on him ? Isnt it
harmful for your own life ?
So I say revenge is not needed.
Unless if it is something that is not only related to
you......for instance someone wronged your family, loved ones, your
friends who you care, or something that is very important as a
matter of principle, then maybe yes, for their sake you may need to
take additional actions.