What should I do after I fall to protect my rights?

The first thing you want to do is make sure that you are in the condition to move. If you are so injured that you cannot move, then you want to alert someone to come and assist you. You want to report that to the management, to the supervisor on the floor, as early and as soon as possible. Then you want to start taking pictures. You want to preserve your clothing, you want to preserve your shoes. You want to document every possible thing you can at that moment.