Hello. Thanks for writing in.
How long ago did you first notice this lump?
Has it grown larger since you first noticed it?
Is it on top of the skin or under the skin?
Is it firm or soft?
Is it freely movable or fixed in one spot?
Hello, again. My suspicion is that there is an ulceration and subsequent infection on the cornea. Shutting the eye closed is usually a reaction to pain. Your vet will need to numb the eye and stain it to look for an ulcer. If superficial, it should heal up with no problems with a topical antibiotic eye ointment. If deep, it may require oral antibiotics as well. Pain medications will most likely be needed in either case. I would have her seen tomorrow for this. If it is an ulcer, the sooner it is treated, the better the prognosis. Please let me know if you have any other questions. Hope this helps.