About 3 years a go, I fell against some barnacle covered rocks whilst on holiday and I got a nasty cut and bruise on my shin. About 6 months later after the bruise had cleared, a hard lump formed on my shin and I'm only starting to get worried as I think it has gotten bigger. I can feel it very clearly and my mother has thought it is a blood clot but I don't think so. What is it? And is it bad?