When Do I Go to the Doctor?

I have high-risk "catastrophic" health insurance. COBRA would have cost me $400+, and any full health insurance would have cost me a small fortune. I also had a lot of trouble getting insurance in the first place (see here, here, and here) so I'm ecstatic to have the minimal health insurance that I have for something like $138 a month. Two days ago I noticed a fairly large, hard bump on the back of my head, a few inches from my ears. It was swollen and throbbing. After doing some research onlin