3 different causes. A stye is an infected hair follicle. It is a large, red, painful bump on the front of the eyelid near the eyelashes. A chalazion is a backed up oil gland that forms a deeper nodule with overlying red skin. It is rarely painful and can hang around for awhile. There are many eyelid tumors including basal & squamous cell carcinoma, melanoma & sebaceous cell carcinoma, which can mimic a chalazion.