I would suggest consulting with your family doctor to see if you may have a sinus infection.
The other over the counter suggestion is to irrigate your sinuses with a netty pot and saline solution. You can purchase a kit at the local drugstore (at least in the US). You mix a saline powder solution included in the kit with clean tap water and irrigate your sinuses. The water goes in one nostril and comes out the other. The pot looks like a small Alladin's lamp with a long spout. It is very helpful for nasal allergies too. My daughter has been using one with great results. She does it herself over the sink without difficulty. She had a bad cold with lots of congestion and green stuff coming out of her nose and doing this twice a day has really cleared it up. Other people I know have also used it periodically with good results.
Hope these suggestions help. Going to an Earn Nose and Throat doctor would be a good idea to rule out serious infection which may require antibiotics.
