What can you do if you make the wrong decision?

Well, this very much depends on what type of "wrong decision" it was. If you wronged a human being, you should apologize. If you wronged an animal, you should apologize. This is all highly opinionated and really only matters depending on your morals. If you made a wrong decision, all you can do is either a. try to fix it, b. don't make that mistake in the future, c. move on with your life.