I am 15 years old and not sexually active and I have small sensitive bumps under the penis head. The bumps are very tiny and get bigger when I have a erection. If the bumps are stimulated it cause me ejaculate very quickly. I have had this bumps ever since I masturbated without lube. I would like to find out what they're and how to get rid of them.

They will be with you as long as you masturbate. That is how you get them. Put two and two together!