I don't think an infected maxillary sinus could cause dryness issues, I would think it would add to extra pressure and post nasal drip for most people, a good person to ask would be Dr. Murray Grossan, he answers questions on his website as well as on facebook (but I assume you don't have access to facebook right?) he answers questions on the "Empty Nose Awareness Group" site from time to time.

Here is his website: http://grossaninstitute.com/

Opinions are like belly buttons, everybody has one....My views and thoughts only,
Although I have personal experiences, I am not qualified.