Hello and welcome to the forum. Sorry you haven't been feeling well. You can always call and ask your doctor these questions for guidance. Flonase is known to reduce nasal inflammation over time. The best thing is to blow your nose prior to using it and then wait as long as you possibly can before blowing your nose again. The longer you wait, the better chance the Flonase has of being absorbed into your nasal cavity. The most common recommendation is 15 to 30 minutes to wait to blow your nose after using.
Let us know how it goes!