I had that same situation this year, a few weeks ago. I actually hit the deer in the shoulder. I gave him almost 2 hours, and began to track him. I ran out of blood late at night, so I decided to pull out for the evening and come back the next morning. It just so happened to have rained overnight, washing away all the blood I had tracked the night before. My grandfather and my uncle looked in the morning for me and did not find him, so I went out for almost 5 hours that evening combing the area. I even asked the neighbor to just look a little ways on his property, just in case he jumped the road. No deer for me. It sucks because that would have been my first deer. Make sure you go out and try as hard as you possibly can to find this deer. You owe it to him!