Yeah the 1 1/4" hex head is the drain for the pan.
On spin on filters you can drive a long handled screw driver though the filter and use the leverage to remove, but in the worse cases the sheetmetal can tears, and you have to clear a way what's left of the filter until you only have the base on the head, then insert two punches in the holes in the base about 180 deg apart and a bar between them to screw off the base.
WHen going back on with the new filter a little lube of some kind will prevent the rubber gasket from "bonding" to the filter head ( which is what happened this time) makeing it easy to get off the next time around.