When you have a bacterial sinus infection instead of a normal viral sinus infection the bacterial sinus infection will sometimes last longer than a few weeks.
Instead of the normal few weeks that a viral sinus infection typically lasts the bacterial sinus infection can last from 1 month to as long as 4 to 5 months.
If you have a bacterial sinus infection you'll usually require antibiotics to treat the sinus infection and make it go away much sooner.
Sometimes a bacterial sinus infection will eventually go away on it's own however it's best to get some antibiotics and medical treatment from the doctor to get rid of the bacterial sinus infection much sooner.
When you do have a bacterial sinus infection or other sinus infection you should stay hydrated, use a humidifier and get plenty of rest.
Also sleeping with your head elevated as well can help with your bacterial sinus infection.