Tiny bumps on penis skin

Hey my friend asked me if a question; there are small 'bumps' in his penis skin, he described them as really tiny pimples, lol. He said that when he 'pulls' the skin down, he sees them. They don't really hurt or anything but he's scared if it's some kind of disease. He tried scratching them off but it won't work, he's a bit younger than me so he's around 12. And I guess he's been masturbating... What is his problem? He wanted me to find some information so I think it'll be best if I post this question here, can anyone help? His guess is that it's after he pees, he doesn't clean his penis and the urine might just stick there and form those stuff. He also said they look like spores, and that they're really small, like half the size of this aprostrophie: '. There are a few of them but not all over the penis, just some in his skin when he pulls his upper skin down. He also mentioned that sometimes his penis feels sore, I guess it's his masturbating too hard, lol! Also sometimes the 'nerves