Milk bumps on babies is basically just acne that shows up on babies skin due to clogged pores.
Baby acne or milk bumps on babies usually goes away within a month or two months after birth.
The milk bumps on babies are caused by blocked skin pores in the baby and milk bumps or baby acne can appear on the babies face, nose, chin and even the babies cheeks.
They are not harmful and usually clear up on their own.
There's no way to prevent the babies milk bumps and no reason to really need to treat it because they do eventually go away on their own well before the babies 1st birthday.