I have something that looks like a spot just to the left of the skin over my coxic. It has appeared for the forth time yesterday and I am fed up. It I pretty painful and causes numbness aswel. The first time I sat on a chair and it popped I checked in the bathroom and yellow puss time stuff was on my underwear. The second time it just died down after about two weeks. The third time I sat down and it popped and started bleeding, it took me two tissues for the blood. It is quite solid but can be squishy at times. It is red around the out side and a sort of dark black Colour in the middle. Please help x