Hi!
Please have your girl vet checked or make sure that she is seen promptly as soo as you notice signs of ulceration, i.e. a blueish dot or film over the eye. This means that the hay has scratched the eye surface and has caused an infection.
We generally recommend to have any protential eye injury or infection checked by a vet within 24 hours because they can deteriorate very quickly. The damage can be larger than you can see with the naked eye. Vets use a special dye and ultraviolet light to assess ulceration and any damage.
The good news is that with prompt treatment, minor eye injuries also heal very quickly and usually without problems.
Please do NOT use water (which is not sterile) to wash an eye with a potential injury as that could flush bugs into a wound and cause an infection. Even sterile eye wash is not a replacement for a vet visit and cannot necessarily prevent an infection.