As suggested above by @
cyccommute, take the bike to a shop and have them check it out. It may be all that is needed is to straighten the hanger, but to do the job properly requires a specialized tool. There is a risk that straightening the hanger will break it, as the hangers are designed to fail easier than the frame to which they are attached. If that should happen, the shop is in the best position to source the proper replacement part.