If the people of import remain alive and well when you return, nothing is lost. Little really changes in a hundred years.

The past is difficult to change. Events within it either remain the same despite meddling, or the changes spark new universes. Would it not be easier to search for another world where you were able to fix the problem?

Perhaps that is the difference. When one has seen how much worse things can be, one appreciates the little good their is all the more.