If the sinus infection goes untreated and gets worse the sinus infection can lead to meningitis, infection of the bone or even a brain abscess in rare cases.
Sometimes a sinus infection clears up and goes away on it's own within a few weeks but if not then you should see a doctor about it.
You don't want to let the sinus infection go untreated and get more severe and lead to further infections.
You can help ease the symptoms of the sinus infection overnight but to actually get rid of the sinus infection completely overnight is impossible.
When you have a sinus infection some things you can do to help get rid of the sinus infection and also ease the sinus infection symptoms are to.
Drink plenty of water as the water keeps you hydrated and the water also helps to flush the sinus infection virus out of your body.
Eat foods that include Vitamin D and Vitamin C to help boost your immune system.
Use some over the counter nasal spray and clean your nose using a saline solution.
Also use a humidifier in your room at night and in your home to add moisture to the air which is also good at helping relieve the sinus infection.
Take some over the counter sinus medications and get plenty of rest.
Most sinus infections will clear up on their own within a few weeks or so.
If the sinus infection lasts longer than a few weeks then it would be best to see a doctor about it.