Late this afternoon Jack started smiling and playing like his usual self. Justin and I looked at each other and said "I think he's snapping out of it". It was literally like flipping a switch, he was off and now he's back on. THANK GOD. I said to Justin that if you weren't witnessing something like this with your own eyes you wouldn't believe it. You just would not.
We're pretty sure it was that Kohl's cart. Almonds would explain an IgE and IgG response since he's allergic in both respects. Can't know for sure and it doesn't really matter, I'm just glad it's over.
ETA: It was homeopathy!!