He will be six in February. There are no cacti in the area. It won't come off and seems to be rooted. He expresses discomfort if I try to remove it. I will try applying something to soften it.
Yes, it is only that one spot. The white area around it is actually transparent and hard like keratin. The light just makes it look white. I read the article you recommended. I just don't think it is pox though, from what I've seen on pox. It is just the strangest thing. I thought he had a...