A few weeks ago, I saw something developing on my neck. Didn't think it was a big deal, but it keeps growing. It's about the size of 4 dimes stacked together right now. It's a dark color, and it doesn't hurt at all. The sac is very fragile, and when I break it, bleeds profusely. Otherwise it just leaks a clear, slightly odorous fluid. It's just there, really, growing bigger. I have a large bandaid over it at all times to protect it from everything. However, I don't like that it's not going away. What could it be, what course of action should I take, and is there any way I could deal with it myself?