The pox?

Noah has recently had a mild cold but he is completely over that. He has now suddenly come out with watery blisters - 3 or 4 on his chest, one on his shoulder, one above his ear, one on the back of his neck and about 5 or so on his back. When I first saw the one on his neck I touched it and it burst. The ones on his chest / upper back are firm blisters, the ones on his lower back seem to have been rubbed open and now look as if they are healing scratches (i.e. they aren't infected or crusty or anything.)

He is totally well, no fever or other symptoms and insists he is "fine" if I ask him if he's poorly. He isn't itching or bothered by the blisters and they don't hurt if I touch them.

Any idea what this could be? Could it be chicken pox if he has no other symptoms and if he isn't itchy? He's not had any different food to eat or any new products on his skin - I don't think they are allergies.

They may look like pus-filled zits in these pictures but they are actually watery blisters, no pus at all.