I have a svere sinus infection. What is the best way to treat this?

Agree. Antibiotics are usually essential, but irrigation of the nasal passages, decongestants, sometimes nasal steroid spray and medication for pain may also be helpful. Establishing adequate drainage is needed.
Sinus Infection. If it is a bacterial infection, you need antibiotics. If it does not go away, you may need to see an ENT physician to see if the sinuses are draining. You may even have allergies that set you up for infections. First step is to start with your pcp and get on antibiotics.