Most health insurance companies have a reimbursement/subrogation clause in their contracts which require you to repay them for benefits they paid on your behalf, if you collect money from a third party (such as your Personal Injury insurance).

So if the Personal Injury Insurance you bought as coverage on the rental car paid for some of the same medical expenses that your health insurance carrier already paid than normally you would be required to repay your health insurer. If the car insurance check to you was to pay medical expenses that were in excess of what your health insurer paid or for different expenses than what they paid you may be able to keep that money.

To make sure that you are following the terms of your health insurance policy and will not be come after at a later day to repay them monies take the time now to check with your health insurer about your situation. Their claims department should be able to advise you if need to repay them any money from your Personal Injury settlement check or not.