these explain them pretty well
link to sebaceous cyst:
http://en.wikipedia.org/wiki/Sebaceous_cyst
link to abscess:
http://en.wikipedia.org/wiki/Abcess
hey there, i've had two sebaceous cysts so this is what i've learned..first off, they aren't contagious so theres no need to worry about that. their primary cause is irritation of sebaceous sac withing a pore/hair follicle and blocking it up and not letting it sweat or ventilate...so i'm guessing its right around your belt line? i had gone to a mountain bike meet for a weekend in the fall and had worn jeans and a pretty tight belt, so after two days of sweating and getting dirty i found a cyst right where my belt line had been for that weekend. The simple way to get it taken care of is going to a dermatologist, tell em whats up, and theyll usually inject the area with some anesthetic and just cut it aka lance it...and then theyll squeeze out the fluid and thats it, it simply heals up and disappears and after a month theres no scar...if its deep though youll have to get a minor surgery, thats what i needed on my other one, they just knocked me out for an hour and scraped out where it was, then sewed me back up, and there's no scar to see there either which is great.
but to distinguish an abscess from a cyst think of this...the cyst will mostly be skin colored with a bit of paleness to it, while the abscess is more of an infection of the tissue under the skin from when something with a bad bacteria pierces the skin
and what ever you do, dont pop it anymore, thats how it gets irritated and infected and it can get bigger and its pain, so just give a dermatologist a call and let him know you have what you think is a sebaceous cyst and all will be right in the world again haha, but its nothing to get your head wrapped around