I hate to say it, but I would definitely take the kitty back to the vet. It sounds like she is still in pain. Or maybe, if she can look in the kitty's mouth to see if anything looks swollen or "angry red" and then make a call to the vet. Explain everything, including what she saw in kitty's mouth and maybe they can just give her a pain killer or something. The vet might say something like maybe this is somewhat normal behavior and she'll come around, or this is absolutely unusual and you should bring her back ASAP. At the very least I would at least make the call, and if he suggests bringing her in, well then better safe than sorry, right?