Sinus Medication Solution

I have doxycycline left over from a trip to africa. it is used for malaria prevention. i now have a sinus infection that wont go away. i looked up doxycycline on line and saw that it is used for certain infections but sinus was not listed. the articles say that it may be used for other purposes not listed. will it kill a sinus infection?

I’ve had a sinus infection for five days. Huge pressure, pressing on my teeth and now having ear pain – no congestion, only feels better when I take decongestants and ibuprofen. I know – go to the doctor. I’m uninsured and a starving artist, can’t afford it. I have some doxycycline left over (about 10 days worth)…will it work on my sinuses or will it just do nothing?