So I've had my pet rat for about 5 days now. Around the second day of owning her, we noticed that she did not use her hind leg when walking and kept the foot curled and close to her body. Out of concern, I picked her up and very gently felt around the ankle and foot. She did not protest and at all and gave no indication that it hurt when I applied pressure. I even flexed the foot and ankle with absolutely no indication of pain from her. We decided that perhaps she just had a lame foot since there was no pain and that we'd watch for anything more in the following days. Today I took her out of her cage for a bit of personal time and I noticed immediately that her ankle area had become swollen. We played just last night and I did not notice any swelling before. I'm not sure what I should do. I've read that Metacam helps with this sort of situation. Do I go to the vet for a prescription? Where can I get this?