Hello!
There is usually bacterial overgrowth within the sinuses that trigger inflammation. This inflammation leads to tissue damage. I would be addressing the bacterial imbalance (using antifungals) and then taking antiinflammatories such as Curcumin. You may also want to consider antivirals also. Also, if you are breathing in toxic chemicals, smoke, fragrances, etc, it could be irritating the sinus membranes. Vaccinium Vitis Idaea Gemmo is great for mucous membranes however I am not sure if it is available in your country. Lastly, glutathione (liposomal) cna help repair mucosal linings.