Sinus Season

I've been told that if you blow your nose and the tissue is full of brightly colored gunk, then you have a sinus infection. And I've been told that these infections can only be treated with antibiotics. I don't know if there's any truth to this, because I've blown neon-green gunk out of my nose and never gone on antibiotics, and it's gone away on its own. Whether this is because I'm a superhero with the power to produce my own antibiotics or for some other reason, I have no idea. I bet that when I die they'll conduct an autopsy and say, "This is the most advanced sinus infection we've ever seen in our lives."