Styes are a common infection of the eyelash follicle. Most people develop a stye once or twice in their lifetime. Styes usually show as a small painful lump in the eyelid over 1-2 days. Often, a yellow spot can be seen in the middle of the lump on the outside of the eyelid. Other symptoms include a watery eye and a red eye or eyelid. Styes are caused by an infection of the eyelash follicle. The follicle fills with puss which causes pain and tenderness of the eyelid. Styes are more common in people with long-term blepharitis, therefore managing blepharitis with lid hygiene is usually advised. Most styes get better without treatment within a few days or weeks. Styes may rupture and release pus after three or four days. A warm compress held against the eye encourages the stye to release pus and heal more quickly. Further treatment is not usually needed unless you have a very painful stye that is not getting better or a very swollen red lid indicating spreading infection. In this case, you should see your eye-care professional who may decide to treat you with oral antibiotics or advise additional treatments.