Most styes are harmless and will clear up on their own in a couple of weeks, but you shouldn’t self diagnose.
If it’s a stye, the skin around it may be swollen and red and the stye may be filled with yellow pus. The redness may be harder to see on brown and black skin.
Your eye may be red and watery but your vision should not be affected, and styes usually only affect one eye but it’s possible to have more than one at a time.
The NHS site recommends seeing your GP if the stye is very painful or swollen or impacts your vision.