Please see an appropriate ENT Consultant/ Rhinologist, who may help with diagnosis through routine blood counts, Sinus
X-ray (digital)/ CT/MRI
Sinus examination and treat it further as it may be required. The treatment of sinus due to infection is 14 days (approx) antibiotic treatment or until the repeat x-ray sinus report reverts normal. However there could be other causes also which may need treatment accordingly. Please see suitable doctor in your vicinity/area. Thanks.