The point is that the expression ‘green hand’ is simply not in use in modern English. Most people have probably never even heard of it. And even when it was in use in the past, it was restricted almost exclusively to maritime contexts, specifically meaning a new recruit on a ship. In short, it’s an archaic term familiar only to readers of Mark Twain, and you’d do well to forget it altogether.
And as far as I can see, in Collins there’s only one mention of “appearance” in relation to the word
person, and that’s also very much a fringe/rare use:
person
3b. bodily form or appearance (ex: to be neat about one's person)