Okay, good thoughts.
These are BRAND new spots. He's had NO spots for three weeks, so it seems odd that they'd be infected spots. And they don't seem infected, just that creepy yellow blister and crust.
What's the deal with impetigo? This isn't in one section only... Three on belly, one in butt crack, one on scalp, two on shoulders, two on lower back... ALmost EXACTLY where the supposed pox showed up. But his skin was 100% clear for 3 weeks.