Hello, I've Had A Blood Filled Boil On My Butt

Hello,

I've had a blood filled boil on my butt cheek for a couple of months now. I first thought it was just a deep pimple and it would go away but recently I had acidentally punctured it slightly and it oozed a bit of dark blood. I'm worried that it might be either a cyst or a staph infection and would like some information on what exactly the boil is