I think they're from masturbating. Have you heard of this before? Can I get rid of them?
First, the bumps are not from masturbating. Second, they are very common. Third, no, you can't get rid of them.
The "bumps" have to do with hair follicles – either hair will start to grow out of them soon, or (if you're an adult) they are formed by hair follicles that never actually began growing hair.
Let me once again take this opportunity to stress that masturbating does not cause physical effects in your penis like bumps, different-colored areas, or reduced size. If you make this kind of connection, it means you're assuming there's something wrong with masturbation – that you shouldn't be doing it, and that since you're doing it anyway, you're being "punished" with some kind of physical "defect." Feeling a little guilty about giving ourselves pleasure, are we?