With all the things consitered, I would have to go with Aloft's answer, it is a work related injury, so there will be no financial harm to the FA, the only problem is getting the company to fork over the money to pay for medical care. The pax will have to deal with the delay, the FA is a required crew member and must be on board and able to perform all the duties. Hell, comp them some drinks to shut them up...
Sometimes the company does understand that Crap happens and sometimes that Crap delays a flight.
Marilyn