The meat should be fine but if you' re sure of a good hit why let it lay? I' ve read too many stories of those damn yotes beating people to their kills. Me personally if I know the hit is good(and by what you say 20in. of penetration,if you hit vitals it was a great hit) I would stay out until I found the animal. I keep a lantern in my trunk and stay until the deed is done. With that said, if you were unsure of the hit you made the right call. I wish you the best of luck this morning!