Hi,
The chicken pox is caused by varicella zoster virus. Sometimes this virus can affect the eye too. When there is an infection, if the cornea is involved, it can cause irritation, pain, watering and decreased vision.
Next Steps
its better you get yourself checked by an ophthalmologist to rule out the eye infection due to varicella zostervirus. For the watering and foreign body sensation, start with some lubricating drops available in the pharmacies, 3 times/day.