What Causes Itchy Painful Red Lower Eyelid With Yellow Spots Inside Eyelid?

I have had itchy painful red lower eyelid with yellow spots inside eyelid but no pus. Before this happened my eyes had been watering badly for three months due to chemo I was told. A PA saw me and said it looked like a plugged tear duct and prescribed erythromycin ointment and warm compresses. After a week it is a little better but moe yellow spots have appeared and still red under eyelid and itchy. Not watering. When I put artificial tears in eye it drains into my nose so I do not think it is a plugged tear duct. My eyes are not watering or dry. What is going on? Other eyelid fine and no yellow spots inside. I have opthomology appointment but not for three weeks.