How do I know when my belly button is infected?
Did you get it pierced? Or do you mean just from a build up of body goo your belly button may sometimes get? If it’s a piercing, it will be inflamed, probably ozzing puss and/or blood. A solution of warm water and sea salt should help clear either of these. Just get a cup and lean down on it until the cup seals around the skin, then carefully lay on your back. Soak it until the water gets cold. Do that until it heals. It’s what i did for my infected piercing.