Did you check her paw? she might have gotten something stuck or a small cut, maybe split or broke a nail??? Vegas pulled both leg muscles within the last 6 months. I laid him down did range of motion (bending hip, knee, ankle) all was working fine, ended up taking him in, he got a cortisone shot in his leg, nothing more than a pulled muscle. I had to keep him off furniture and from jumping around for the next 3 days. I would not really go to the ER, wait and go to the vet, she is obviously Ok until tomorrow. Keep her rested though, no jumping or running. Keep us updated please.