First of all on a shot you felt was bad you moved in to fast! You shoulda waited 8 hours before even attempting a recovery.

I'd bet he went out into that golden rod field and layed down. You'll have to carefully search it to the point where no deer could lay there without you finding him.

Are tracking dogs legal where you are at? If so you can go to one of the blood tracker sites (Rob/PA) could help you find someone, in your area. PM him.