Vaccines do not cure anything. A vaccine stimulates your own immune system into making antibodies against an infective organism.
When you get an infection, there is an incubation period during which you don't show symptoms of disease. If you take a vaccine in the meantime, you can prime your immune system to react to the infective organism when it becomes active.
Rabies can often take a month to incubate and show symptoms, a year is not unknown, and there is no real cure. Even if you feel OK you might be infected.
There is a chance that you might react badly to the vaccine, but that risk is slight. If the choice is between that and the chance of catching rabies, I would take the shots. In the large majority of cases the worst thing that might happen is that you would become immune for no reason.