If it's an injury, limiting her mobility is a good idea. Also, heat may help.
Last year, I had three pullets afflicted with lameness. You can read this thread https://www.backyardchickens.com/threads/five-month-old-australorp-suddenly-lame-update-now-another-pullet-going-lame.1432738/ to...
How old is she? On the chance this is just a deficiency or a temporary nerve inflammation, you can try treating her with vitamin B-complex. Get the B-100 or B-50 complex from the store in the people vitamin section. One a day directly into the beak until she is back to normal.
There's a chance...