What causes bumps on the tip of penis?

Get checked: One man in 100 is the lucky owner of "pearly penile papules", a row of bumps along the corona on the back of the gland / head. They are a harmless novelty. Or you may be describing warts, which need to be treated. Good luck.

Could be normal: Pearly penile papules are white or flesh colored bumps rimming the penile glans. They are benign and require no treatment. They can be treated with a laser, but this is not necessary. Other bumps could be an std and some of these would be painful. You should consult a physician.