Here's how Shelly herself describes the wretch. "His yellow skin scarcely covered the work of muscles and arteries beneath: his hair was of a lustrous black, and flowing: his teeth of a pearly whiteness; but these luxuriences only formed a more horrid contrast with his watery eyes, that seemed almost of the same colour as the dun white sockets in which they were set, his shriveled complexion and straight black lips."
I figured if his skin was translucent from being stretched so thin then it would have been difficult to keep the ends together when sewing. So I made sure to show some exposed meat beneath the skin at the seams where the stitches are barely holding him together. It was a myth for years and years that your hair and finger/toe nails continued to grow after you died and I wondered if that's where Mary Shelly's idea for his flowing black hair stemmed from so I gave him long claw like finger nails. I also skewed some of his parts so he wasn't quite put together right, which is why his abs kinda stick to the one side. I also cut a hole over his heart and then stitched it back up cuz I figured a delicate organ like that might've required frequent reaccess while he was being built. And I reasoned that he might not have a lot of cartilage left in him either which is why I pulled his nose back like a skull. This isn't a bad drawing but I think if I were designing him to appear in a movie or something I'd take a couple more passes. I'd probably experiment with the stitching a bit, maybe see how it would look if it were more excessive and I'd definitely play more with his posture.
Of course...there's still a lot to be said for the classic...