I've noticed, probably in the last year, a small, hard lump appear on my ball sack... feels like a half a grain of rice under my skin, about that size anyway. It's the only one I have and I haven't noticed anything else apart from this. I've uploaded a pic of it so that maybe someone can identify it and please let me know what it is? Doesn't feel like it can be burst like a pimple but I haven't tried really hard to. Thanks for your help.

http://img.photobucket.com/albums/v497/AUsome/IMG_0070.jpg