The after I posted the scours cleared up. We still don't know what caused those, but this isn't our first kid to have a brief attack of diarrhea.
However. The nose swelling turned out to be an abscess begun by an infected injury inside his right nostril. It grew to be about three times the size of what it is in the photos I shared. We treated him with Sulmet and a doctor friend offered to lance it for us. There was a lot of yucky stuff in there! Once we got that cleaned out it began to heal. Little Nod is now recovering. He is still a bit weak from going through all that, so we're making sure to keep an eye on him. : )
A big thanks to bighooves , sarahshevett , and reedrover for the advice and tips they shared! That was very encouraging and helpful. : )