Hmm, like I said, at this point the problem is less mucus/congestion and more just outright swelling of my sinuses. I know for sure that I had (still have?) fungus in my sinuses, because every morning for months I was blowing out doughy, sticky white mucus that became clearer and clearer once I started adding a drop of tea tree oil to my neti pot. That's why the explanation that makes the most sense to me is that there is still some fungus up in my sinuses, and the swelling is my body's reaction to it.