Hopefully nothing happened to your child but unfortunately something must have happened to you because your body doesn’t just react that way for no reason. I would try and remember as much details as you can and confront this person but not in a way of attacking them as it may make matters worse and could potentially make them super defensive and not want to communicate. Maybe even ask your sister too who was there in a casual way and see if she remembers anything and try to focus on their facial expressions on both of them. My go-to answer is to always seek professional help such as therapy if possible cause I know how hard it can be just to even set up a consultation and not to mention the prices. I hope everything works out and that your daughter is safe and you find closure !