Attacked By "service Dog" Today, What Should I Do?

Today I was sitting in the waiting room at the hospital minding my own business looking at my phone. Suddenly a dog came around the corner and attacked me. He bit me on my leg. I did hit the dog in the head to get him off of me and grabbed him by the scruff of the neck and pinned him to the ground. I was sitting next to a little boy and didn't want the dog going after him or anyone else.

The police were called and 9 people in the waiting room made statements in regards to what happened. The owners stated that he was a service dog when they entered the building. The lady did slip and accidentally say he was an emotional support animal and couldn't answer the police when they asked what tasks he performed for her. They also tried to lie by saying the dog was her mom's and he was current on rabies. The dog was not current. The dog was wearing a vest that said service dog and was on a flexi leash. This is apparently the dogs second offense.

The police told me that the couple said they were going to sue me for hitting their dog and "detaining him against his wishes."

Should I be worried? I really can't afford a lawyer as I am currently disabled. From what I understand, lying about a service dog is illegal in Minnesota. I was just trying to protect myself and others, and honestly didn't injure the dog. I was a vet tech for over 20 years and this is the worst bite I've ever had. I feel bad that the dog has dumb owners and will probably end up euthanized.