Han Sen did not like making wishes. He knew what had happened to Dawn, Uncle Bug, and the Ning family's Second Mister, and it had completely soured him on the concept of making wishes.
Han Sen did not think Skygod was a good character.
Chiron Earl had made a wish, but he was killed alongside the rest of his helpers.
He did not know if Wind Viscount had made a wish, but he had died, too. And on top of that, he had infected the rest of Han Sen's people back at base with the sacrificial marking.
Han Sen did not say anything. And there were only two wishes he could realistically make. One wish was to ask Skygod to erase everyone's markings, but that was something that Skygod was suspiciously leading him to request. If he wasn't leading Han Sen on, he wouldn't have mentioned the possibility in the first place.