Garlic is powerful against parasites, and parasites are actually known to reside in the sinuses. Many reports here on curezone, myself included, but I am in contact off this forum daily with many who have them in the sinuses.
There are many different parasites, the most common though is a type of Ascaris that likes to take up residence there.
I suggest you up the garlic. It not only works against parasites, but acts as an Antibiotic and will help infection in that area. You will get worse before you get better.