What Causes Dark Spot In The Urethral Orifice?

Hello, I notice two days ago...a tiny little dot on the meatus on the tip of the urethra opening (above)...what could it be? it doesn't hurt, or bleed, or its bumpy...its like a blackhead...what could be? I think it happen when heavier pressure (than usual) was applied...could it be blood clotted in there making the small black/purple dot?