It definitely takes a while. And *if* this is nutritional, you'll need the actual B - as it's a B-complex and involves a number of B vitamins which aren't included in the polyvisol.
I'd leave the roll off of her, maybe put it on her for when she eats? a) that way she associates it with eating, and b) to keep the water/food from running back up into her mouth and causing aspiration.
This is never an overnight cure, no matter the cause. Sometimes these things are even inherited, happening at a certain age (though often enough they're not).
If the bird were presenting any respiratory symptoms (sneezing, coughing, excess mucus from respiratory problems not head location, congestion, eye drainage, nasal discharge particularly that with a sort of mellow cheese or sour smell, not fetid) then I'd consider pasteurella (cholera) which usually isn't that common. Because it's not presenting with these symptoms, yet, I don't think I'd treat for them just yet.
I think perhaps she's feeling better and that's the problem - she feels fiesty now.