It's a trip to the doctor.
I could list of 25 things it MIGHT be... but a doctor could actually tell you.
Aw, shucks. Here's the short list:
- Pimple / Boil
- Ingrown hair
- Folliculitis (bacterial, viral, or fungal)
- Bacterial infection (dozens of common kinds)
- Viral infection (dozens of common kinds)
- Fungal infection (dozens of common kinds)
- Cyst (about 20 common kinds)
- Parasite (insect, worm, etc.)
- Spider Bite
- Egg sac (insect, worm, etc.)
- Foreign Body
(pencil led from 3rd grade when Jimmy got you to a bead, to an undisolved suture, to all kinds of stuff..things migrate in the body. I knew a boy who slid down the stairs on his mum's ironing board, got a needle in his rear, and it exited out his thumb)
- Bone fragment
- the list goes on, and on, and on.
And whaddaya know <grin> instead of 25, you got about 200 possible things on the list
But 5 minutes with the doctor, and labs on the exudate -if cause not immediately apparent-, will actually tell you.