From my experience, a tutor can tremendously help in anything you are weak on. However, how much you improve (if at all) depends a lot on the quality of the tutor and the amount of work you put into it. Before you commit to a tutor, I suggest using any and all resources you have at your disposal. Most specifically, focus on the AAMC CARS questions packs. If you find that you are not improving after a month of going through those passages, I suggest seeking additional help.