Book about a man whose travels appear on his skin as a map

[Pamela]

The man comes from a tribe, all have this curse?/ mysterious ability?
One is captured by people that want to use his skin as a treasure map, so they skin him to make the map flat, so as to copy it. He's kept alive so the map doesn't fade. I read this about 30? years ago and I'd like to re-read it. It isn't The Illustrated Man or The Skinmap