For years I've had infrequent blister-like lumps appear on my pubic mound. They are usually oval, singular, and a little squishy when touched with a harder bottom. They never rupture or develop a head, or become crusty. Lately I've been getting them more and more frequently, and usually in the exact same spots. I've poked them with a needle to try to drain them before but nothing but a tiny amount of blood comes out. What on earth could this be??