"Besides a tiny piece of white hair 10 yards "
This would indicate alot of times a lower shot, maybe the exit hole came out low, or you hit him alot lower than you think.... i would think if you hit him where you posted the pic, and exited low, you would have possibly got a lung, maybe even a heart as well...
Same thing happened to me, hit in the same area you posted, and the arrow stayed in him... but found 0 blood, but did find him after 60 yards...
Sorry to hear, I know first hand how bad it feels when you realize...