The exploremap devcommand doesn't actually generate the revealed areas, it just removes the "fog of war" from everywhere on the map. Likewise, resetmap just puts the fog back onto the map (including for areas you've actually explored). As long as you haven't actually come within around 500 meters of a zone, then its contents has not yet been generated (even after using exploremap) and will (most likely) provide the new stuff when you get there.