i just dealt with the same thing last week. go see an eye dr. not a reg general dr. i did that and the first dr put me on some ointment and said i had pink eye, but after a week it didnt go away. so i went to the eye dr and come to find out i had a cornial infection, not pink eye. and instead of the ointment, i should have been on a steroid eye drop. hope this helps.
Go see a doctor. Could be a stye or some sort of infection. There might even be a bug or debris in the eye.
It sounds like a possible cyst or infection, however, if it is slowly swelling shut - I would absolutely visit an eye doctor and clarify that (1) it is an emergency and (2) their ability to treat "in office" versus just "diagnose" and (3) ask if there's anything they can prescribe to keep you comfortable between now and your appointment...