No, your medication (montelukast and fexofenadine) does not cause green discharge. Instead, the green discharge and increased congestion suggest a bacterial sinus or ear infection has developed. To treat this, your doctor may prescribe antibiotics, nasal steroid sprays, or saline rinses. While these alternatives can clear the infection and temporarily relieve congestion, they cannot correct the physical bend of a deviated septum. If the blockage is purely structural, surgery is often the most effective long-term solution. I recommend discussing treatments to clear the active infection with your doctor first before finalizing any plans for surgery.