you dont mention if its under the skin, or on the skin. or if it moves freely or seems connected to things
not that it matters, just go see a doc!
it will either be a Cyst, or enlarged / swollen lymph nodes.
both are sign of infection. lymph nodes are there to filter out toxins.
sometimes lymph nodes can be nothing more than your body catching out the toxins in your body, related to a bad flu. other times it can be a symptom of another health problem.
you really should get it checked by a doctor as they will be able to confirm.
i mean like, go to a doc ASAP and they may refer you to get tests done if it is out of the ordinary.
It could be a boil.... boils are caused by hair being pulled and then it bounces back in the skin then dirt and oil...so it's basically like a big giant pimple.... but id go to the doctor if it doesnt go away and if u've had it longer than abt a week....
It could be just a cyst! Have it checked by your doctor just to be sure.