Do you think something happened at the groomer ?
I wonder if they did something to twist her leg ....
My Chanel limped once (for a few hours) after running too fast and it broke my heart..she never acted different or in pain and I was ready to go to the vet but once I kept her quiet for a while - she started walking normal. She never 'collapsed'- that would have had me rushing to the doctor
I hope she'll be ok - That's awful that she collapsed
...I have no advise but wish you all the best and she gets better very quickly.