What could be wrong with my dog?

My 2 year old female Pomeranian recently got in a little fight with my other female dog over some food. I'm pretty sure my older dog bit her or maybe hurt her somewhere in the backside area. For the past 2 days my Pomeranian has been laying in her kennel. We practically have to handfeed her food and take her outside, because she hardly ever comes out except for when somebody is at the door or something. Sometimes, at night, she tends to whine a little bit. She might of gotten spooked because of the fight or has gotten hurt in a way. My family and I scheduled an appointment for the vet for tomorrow, but I'm just curious as to what it could be.