ditto Matts comments but I would wait till tomorrow to let the buck lay and stiffen! Also its much easier to track in daylight WEATHER PERMITTING! Lantern tracking works great but can sometimes be difficult. The buck is going to need time, give it to him and start over again tomorrow!

Look for water, thick cover, and movement corridors that the buck might use to aid in your searching! Do semi circles when you loose the blood to maybe find it, or the buck! If you find where he is bedded and you DONT push him out or another animal doesnt, he should be within a couple hundred yards of there in the morning stiff as a cardboard box....no matter what happens, that animal is dead, and I wish you the best of luck in recovering him!