I agree with Rob. The likelihood that your buck will live, considering where you hit it, is small.
If you want closure, you are gonna have to cover the territory to git-r-done. Many times, deer will return to the place they were hit and die there. If you don't think it likely for some reason, think about whatI said about the core area. Maybe you have some idea of where that could be and don't be afraid to try several of his likely daytime bedding areas.