I am going to get my nose pierced but i have blackheads and oily skin. how do i get rid of this problem at home and should i get it pierced, what should i do?

One at a time: Would suggest getting your pediatrician involved in the overall decision if and when to have your nose pierced. The fact that you have acne will make you prone of getting an infection around the piercing that will remain a source for local mechanical irritation and having your acne first addressed and controlled would be recommended.