Ponito's skin was absolute perfection this morning (although there are clumps of baking soda everywhere on his bed now). So I guess I can assume it was something on the new stuffed animals that he was allegic to or maybe a cat chose to sleep on his bed while he was at Grandma's. He's not allergic to the cats, but one of them "escapes" frequently ("You are an INDOOR cat Mr. Snuggles!!") so there might have been something on his fur.
Ponito is not really prone to allergies anymore (he was allergic to glutens as a little guy, but luckily outgrew it), but the Cedar/ pollen in our part of the world is super high right now. There's a saying around here that if you don't have allergies, moving here will give them to you! The airborne allergens could be making him more susceptible to whatever allergens were in his bed.
Obviously I'll wash everything in his bed, but I'm not sure what to do about the new Beanie Baby stuffed animals. He's been convinced by the thrift store owner that they will be worth a fortune someday because they still have their tags on - so I can't wash them. (Good suggestion that it could be bed bugs Purple, but since his skin was blemish free this morning I have to assume it wasn't bug bites).