I've looked for days on end for bucks I hit, and found almost every one too
all comes down to HOW far it went before it died,IF it died, and HOW willing you are to keep looking
4 hrs isn't all that much IMO
doing grid searches helps, possibly getting a tracking dog in can be a BIG help too
a deer can cover a LOT of ground in a short period of time, before expiring
I have recovered deer that went well over a mile, on little to NO blood, by just NOT giving up!
it sucks loosing a deer and it can happen to anyone
I feel your pain
BUT never hurts to look more?