Suggest Treatment For Boil Below The Tail Bone?

Hi, im an 18 year old female and i have developed some form of boil or cyst on the upper part of my bum ( just below my tailbone). It is quite red and farely large, its firm to touch but extremely painfull. I've had it for just under a week and it hasnt gotten any better.. :( i've booked in to see a doctor already but i just really want to know what it is and how it will go away! Please help :(