Can a deviated septum lead to a blocked frontal sinus? if not, what else could cause my forehead to seem stiffer and more uneven on one side of my face near my eyebrow?

Blocked sinus: If a deviated nasal septum blocks drainage from a paranasal sinus it can promote a blockage mucus drainage from that sinus. However I don't believe that a blocked frontal sinus would lead to distortion of a portion of the forehead. A pressure feeling over the forehead is more characteristic. You may describe it as a stiff feeling. Most of us have some asymmetry in our faces.