I'm sorry to hear about that. It is very disheartening to have that happen.

I honestly would say this buck is dead. Your arrow did not completely passthru which would explain the lack of blood at the point of impact. Took a while for the blood to come out of the entrance hole assuming it was high, which it sounds like it would have been (treestand).

I wish you luck in finding your deer. Let us know the outcome.