I've got pimples...in my nose
Pimples in your nose are the worst, babe! I totally sympathize with your sitch. A pimple in your nose is caused by the same thing as a normal, external pimple: Bacteria invading a pore and causing it get inflamed and infected. While it’s not a big deal and is actually pretty common, these buggers can be one heck of a pain.
To avoid getting them, you want to do your best to keep your nasal passages clean. That means not, ahem, picking your nose, and keeping your hands away from your face. Wash your face regularly and change your pillowcase often. If you’re in an environment where you’re faced with a lot of pollutants or airborne chemicals, like a big city, your cleansing regimen is all the more important. Blow your nose when you get home for the night to get rid of the dirt particles lingering there, and try running a cotton swab dipped in a mild astringent right around the inside of your nostril—don’t go digging to China, though!