jan i once had one of them on my chest inbetween my boobidoos a few years ago, i was a bit worried, well alot worried if im honest, but i never went to the docs mind - im the sort to bury my head..
anyway, thankfully it turned out it was nothing to worry about - after a few days i happened to give it a lil squeeze, you know as you do, and some lovely gunk came out of it - just like a snake coming out of its basket when its being charmed! lol .... (strange description i know lol, but tis true!) .. ooh and nicely satisfying at the time it was too ;o/ ... and such a relief it was nothing serious
so hopefully yours is nothing to worry about too cris,
see how it goes and in a few days if youre still a bit worried pop to your docs to put your mind at rest x