Granny (et al), since you wanted an update...
Zachary's toe is badly infected, possibly with Staph, but we won't know until a culture comes back in a couple of days. He was in very little pain by the time his exam rolled around; the toe was oozing some nasty goop but it was closer to normal size and color. I was glad to have documented the worst stage so I could show the pictures to the physician's assistant without prolonging Zachary's pain.
For now, the treatment protocol includes thrice-daily foot baths of warm water and Epsom salt (the semi-helpful remedy we've already tried thus far), plus a Keflex prescription four times a day. The medication may change if the culture comes back with something weird.
After a harrowing half hour at the doctor's office (Gavin was ridiculous, due in part to his incredible lack of sleep and in part to the irony of pediatric exam rooms being utterly non-baby-proof), we made a return appointment for Friday afternoon. Then we drove to the pharmacy (we should get a Frequent Flyer discount at Walgreens), where I explained I need two bottles of Keflex - one for home and one for school.
I came home and put Gavin down for a nap. The world would be a happier place if this baby could get some sleep. Then I talked to Garry, who was finally warm under eight layers of blankets. Tyler had been sharing his sick bed and had been hysterical and uncomfortable for a while, but when I got home he was sleeping peacefully. He was still sporting a fever, even under the influence of Motrin. Garry didn't have Motrin in his system and was burning up as well.
When I returned to pick up Zachary's prescription an hour later, I got exactly what I ordered. I also picked up Children's Motrin, Pedialyte, extra-moisturizing lotion for Garry's cracking skin, and a big bag of peanut M&Ms just for me. I then proceeded to the elementary school, where I worked out the details of Zachary's medicine regimen with the office staff. Apparently several staffers saw Zach's toe and are very concerned about exactly what sort of infection was oozing around the school today. I have instructions to report the lab's findings when I get them.
As for me, I have resolved to self-medicate with chocolate and sleep in the guest bedroom for a few days. I got a flu shot this season, but I don't think it will cover the full panel of Yuck that's floating around this place!