A stye is a lump on your eyelid caused by a bacterial infection. Improperly sanitized contact lens, eye makeup, and conditions like diabetes and rosacea can increase your risk of a stye.

Source: Focus Medica. A small red, painful lump in the edge of the eyelid. Stye is usually caused by bacterial infection. It may be present inside or outside the eyelid on one or both eyes and is ...