Don't worry OP! That's happened to me too. I have MRSA (pronounced: mer-sa) though. It happened to Me the first time on Christmas. Honestly you should go to the doctors and get it checked. If it is any type of staph infection MRSA, you need meds. Just remember to keep it really clean with peroxide, covered throughout the day, and uncovered at night to air.

I had a sebaceous cyst on my arm for about 15 years roughly a 4×4 inch area. I tried squeezing, heat, needles, draw out salve and nothing would affect it. There was no head and it was hard. My doctor said he could remove it but it would result in a giant pit in my arm. It rarely bothered me so I left it alone. I was on a date one night, at the movies, and my date put his arm around me and I felt pain on the bump. When I got home I checked it and it had finally came to a head after all these years. I spent hours squeezing that nasty shit out and some of it did smell pretty bad. It's down to about a 1 inch knot now, which I will be getting surgically removed soon. Sometimes you just don't know when your body is going to embarrass you.

Well I suffer from a rare medical disorder that causes that to happen all the time.. Always happens at the worst time too