How bad is a staph infection in your sinuis? And what other problems will it cause?

Sinusitis. Staph is a very common pathogen in a sinus infection. Treatment is not particularly complicated for this bacteria.
Not good, but... Not too bad. It should be treatable. Staph as a true sinus infection is more common for people with chronic sinusitis. Staph is a frequent cause of infection in the nostril area (which isn't technically a sinus infection). See your primary for treatment, wash your hands before & after touching your nose to avoid spread. If you have a true sinusitis w/ staph, consider ENT consultation.

Related Questions

A year ago, I was treated for a klebsiella sinus infection, now I've been diagnosed with a frontal sinus staph infection. Is this common/normal?

No. This is quite unusual. Either there is something amiss with your immune system, you have had chronic problems with your sinuses, have been treated with too many antibiotics, or have some other unusual problem. Sinus infections, when bacterial, are commonly due to the normal flora of the nasopharynx (pneumococci, strep, hemophilus, and so on). Read more...