A sty is a bacterial infection that appears as a small bump along the edge of the eyelid. It is usually between the eyelashes and may have an eyelash protruding from it.
Stys are usually painful, red, and swollen.
They eventually fill with pus and form a yellow or white head. This treatment should be continued for 3 or 4 days to relieve pain, swelling, and promote drainage of the pus. A sty should never be squeezed or rubbed. Squeezing will make the swelling worse and rubbing may spread the infection. Stys are contagious.