she could have damaged something when striking the rat. if you have ur vet visit coming up then i wouldnt mess with it in case something is damaged. has she been rubbing her face a lot? she looks like she has rub marks on her jaw. that could cause some swelling. you could use a q-tip to gently and carefully open her mouth but i would be afraid if something is damaged in there. hopefully some x-rays can solve the problem and nothing is wrong.