Do you have a dog or know someone with a dog? Would be better if it was a trained tracking or deer dog, but sometimes all it takes is a dog to get curious about a wounded animal scent to find one. Sounds like you broke his leg for sure. If it was high enough, you also got into some lung. We're you way up a tree or on or near the ground. The downward angle could cost you this buck if you were way up a tree. Sadly I know from experience. If you get out there and find blood and all it is is a lot of small droplets, looks like a leg hit. They will also bleed puddles every time they stop on one of those leg hits. A leg hit deer will usually stop bleeding if given the chance to lay down or even stand still for a short time period. Usually your only hope with one of those is to keep pushing it til it bleeds out which is very hard to do without a dog
On the other hand, if you find no blood at all, I would actually be more optimistic. I'm assuming you were using slugs? I have very little experience with slug shot deer, but have a lot of experience with bow shot and muzzleloader shot deer. When you hit a deer broadside in the shoulder with an arrow and it doesn't penetrate the other side, my experience has been that there is usually virtually no blood at all for the first 15 to 100 yards until the deers lungs fill up with blood and they start spewing it out their nose. I've seen the same thing with muzzleloader shot deer. Keep in mind all of these had no exit wound. Sounds like this may be your case and It will be a lot easier to find this deer with a dog in the thicket you describe
At any rate, I wish you the best of luck in recovering your deer. Wish I could help look in the morning.