Hello,
Anything to do with guineapigs eyes has the potential to be serious.
My pig had what appeared to be a scratch on his eye which was looking cloudy. I took him to the vets within 48hrs.
To my amazement the pig sat still and calm. The vet examined his eye and actually swept around the back of it - there it was... an enormous grass seed! The pig did not flinch, he knew he needed help. Afterwards I treated him with oral antibiotics, eye gel lubricant and painkillers as supplied by the vet. 5 days of super long snuggle times he was back to his usual character.
Sounds like something is getting to her... it could be one of her own hairs irritating her eye that’s super fine. A tepid warm eyebath may help sooth and expel any imposter, if at the very least keep it clean until seen by a vet. Are her claws in need of a nip too? The back ones are favourites for scratching eyes and ears in my experience. Good luck.