Without a better picture or being there in person, it's hard to say exactly what's going on. If I were a betting man, I'd say it's a completely stuck shed - not just a bad shed like in the pics in the thread. Dry, stuck skin isn't flexible at all, which would cause the wrinkles. I would follow the steps in the bad shed thread and see how things progress.
Also, proper sheds aren't just the result of what you do in the window just before shedding - it's about proper care all of the time. With him only being in your care for the last two weeks, it would have been tough to course-correct enough to get him through a shed properly if he weren't in the right conditions before. Chances are this isn't a result of anything you did wrong, so all you need to do now is help him through it and make sure he's set up for success going forward. Good luck!