I'm so sorry. This thread started off great and then he died!
Why, oh why do people do this to animals. He probably wasn't strong enough to overcome the severe dehydration and whatever else he was subjected to before you got him. You did everything you could and he was looking very, very pretty. It was a shock to find out that he died.
I got a trinket snake at an auction in that same condition this past April. When he came up to be auctioned they just called him a rat snake, didn't even know what kind! They started him off at around $30 (I can't remember exactly). No one bid because everyone had looked at the animals before the auction and I did too. He looked much like your retic but had a stuck on shed which made him look like a wrinkled old man and he was so skinny I didn't think he would live through the day. No one bid at $30 and the auctioneer kept lowering the bid. Finally at $12.50 I couldn't take it any more and I bid and won him. I hoped he didn't die before I got him home.
On the way home (3 hour drive) I soaked him in some water and he drank and drank. I still have him and, like you did, I wish I would have documented how bad he looked from the start. He's beautiful now.
Yeah, yeah, I know all about not buying dying animals because it only gives the person selling dying animals money to go out and buy more animals to abuse but this time I couldn't help it. The owner had to lose money on this snake becuase I've never seen a trinket on any wholesale list for under $20 and he had to pay 15% comission and a $1 cage charge to the auction co. But I guess I'm a hypocrit because I've posted a dozen times about not buying animals in this shape because it only perpetuates the problem.