Your nose runs on you, you know, nose gunk. And if you ran on your nose then you wouldn't be able to breath through it!
because they nose how to smell
Take it out and switch to a wider ring or long bar. Do warm water soaks to reduce the swelling.
If the piercing is recent, very carefully, once it is healed, you can clean it as usual.
Your piercer will tell you that. You just tell her what side of your nose, left or right.