I didn't watch the video, I am not willing to register on youtube just to see it. But based solely on the posts that I have read here in this thread. It sounds like nothing more than a boil to me. They can get bad. Real bad. They can leave baseball sized voids in your flesh that never fill in. And the duscharge can be unbelievable. I know a guy who had one on his thigh when I was in the Marines and he had to treat himself every day by using an antiseptic and the void was about 3/4 of an inch deep and about twice the diameter of the q-tips he used to clean them. These can be particularly bad if you are diabetic.
Then again...the thing on the video COULD be a spider bite.