This is what you get for using the wisdom of the internet instead of going to a doctor.
This YouTube user, in his description of events, says he used Google to figure out how to treat the cyst on his arm.
The answer — tweezers.
So he pricked the cyst, and it leaks a little yellow goo. But at about the 1:45 mark on the video, he squeezes the cyst and it burst like a volcano, and the cyst gunk spewed on him.
Maybe a doctor could have avoided that.