Tiny flesh coloured bumps on head of penis?

I have tiny bumps on the head of my penis that are clustered tightly together. They are not around the rim of the head, but on the head proper, on the front portion, not on the sides. They make a sort of rough texture, as they are more "steep", and become more pronounced as the penis becomes more erect. They give the appearance of deep lines, like cracks or fissures that reveal the surface beneath, and the bumps are tougher than the rest of the head which is smooth. They do not itch or hurt, or ooze weird fluids, I've had them for at least two years, maybe more. I am a virgin, so I don't think it's an STD. If anyone has this or has any idea what this may be, I would be grateful; thanks!