The answer depends on if there's a judgment or not. If not, you may be able to work out a payment plan that would avoid a lawsuit and judgment. If you cannot pay, they may obtain a judgment that could lead to a lien on your real property, a wage garnishment, or other collection procedures. This can damages your credit, and make it hard for you to get lopans in the future. If you have been sued, you should be able to find out the status with a quick call to the court clerk's office. It...
This is an impossible question for any lawyer to answer without knowing what state you are in, what court any case would be tried in, the nature of your injuries, or the amount of your medical bills. If someone tries to give a dollar amount, you should be very wary of the answer. Case values are so fact-specific, that your best bet would be to arrange a meeting with a lawyer in your area for a consultation.
You should immediately contact a lawyer in your state. Generally, truth is an absolute defense to a defamation action. If whatever you said was factually accurate, there shouldn't be much for your to worry about.