could it be glands called pearly penile papules.. look it up
http://www.chestersexualhealth.co.uk/whats.htm
Pearly penile papules
Just take a look at the picture, where you will see those nice rows of small pearly papules all around the raised up bit at the head of the penis. See the picture - All men have some of them, some men have lots of them, and some have few, but if you look carefully you will always find these little dots all around the rim at the head of the penis. They are normal glands and cannot be removed. They produce tiny amounts of oily secretions that keeps the skin healthy. If a man has a circumcision, it obviously dries out the head of the penis and these gland areas, and they often become extremely difficult to find.
Both males and females produce smegma. In males smegma is produced and accumulates under the foreskin of uncircumcised individuals; in females it collects around the clitoris and in the folds of the labia minora.
Smegma is invisible, noticeable as a smooth or moist texture until it is allowed to accumulate, when it takes on its characteristic texture and appearance described in many texts as "cheesy". Since smegma tends to accumulate under the foreskin in males, its presence is less common and less noticeable in circumcised males.[2]
The subpreputial moisture keeps the glans moist and may lubricate the movement of the foreskin. However, if allowed to accumulate and decay in the foreskin cavity it can provide an ideal medium for potentially pathogenic bacteria to colonize;[3] current medical opinion is that allowing smegma to accumulate freely is unhealthy
well, im female but dont know if this helps or if its like yours, but my boyfriend has a small circular formation of tiny tiny bumps on the underside of his penis, that is hidden when the foreskin is around it, much like you described. They are so small its like little gains of sand, but they have always been there on him. It seems like it would be the same thing, so i dont think it is any big deal. You can always get it checked out if it bothers you that bad to put your mind at ease.