Has she always had it or is it something that has recently appeared? Dogs and cats can have a condition called cherry eye but I don't know whether hamsters have a third eyelid, so may not be the same thing.
When my guinea pig has poked herself in the eye with hay twice, the vet put a liquid in her eye that showed up the damaged area green under a special light. She was given ointment and it healed in under 10 days.
Your hamster may have something in her eye making it sore. I would take her to the vet. She might need to have sterile water squirted into her eye to wash an irritant out ( like many moons ago my cat did when she got too close to me loading the dishwasher and got powder in her eye)