A stye is a bacterial infection of an oil gland in the eyelid at the base of the eyelash. This results in a red bump on either the outside or inside of the eyelid. The internal styes are due to an infection of the meibomian gland and the external styes are from an infection of the Zeis gland. A chalazion is a blocked oil gland WITHOUT infection. These are usually in the middle of the eyelid and not painful but sometimes will become so large that the eye will close. Both of these blockages can be triggered by poor nutrition, sleep deprivation, lack of hygiene and water, and rubbing eyes.
Using a warm compress and occasionally an antibiotic eye ointment, these glands will most likely be cleared up in a few days! A hordeolum will rupture and discharge material (pus) relieving pain within 2-4 days. A chalazion will rarely spontaneously rupture but when it does it sometimes erupts through the skin over a 2-8 week period. Recurrence of a stye is completely random where the occurrence of a chalazion is common.