Your Mucus Is Yellow/Greenish
A colored discharge—as opposed to clear mucus—from the nose or down the back of your throat is another sign you may have a sinus infection, although it’s not always an indication that you need treatment. In fact, the yellow or green tinge can stick around for a few days or even weeks after the infection is over because immune cells are still draining. “It’s basically pus,” Dr. Papa says.