What does it mean if an mri says mucosal thickening in sphenoid sinus? i have sinus pain over my eyebrow. doctor said i did not have a sinus infection or give me antibiotics?

Mucosal thickening is an inflammatory reaction with hyperplasia of the mucous lining of the involved sinus. It can result from many different causes other than infection. Your physician did not believe you had an infection hence no prescription. But the cause should be determined to alleviate any symptoms you might have.

The thickened lining if the sphenoid sinus,which is located behind the nose between the eyes, indicates past infections. If you're now experiencing pain in that region there could be an active infection with blockage of mucus drainage from that sinus. If you had a recent headcold, it would make that scenario even more likely& I'd vote for a course of an appropriate antibiotic at this time.