Ntness....if the animal that bit the dog had rabies and it broke the skin, the dog would have gotten rabies with symptoms within 10 days. Even if it had it's rabies shots, it would have gotten sick without more shots and would have been sick enough to be noticeable. So the original bit couldn't have come from a rabid animal. The dog would gotten sick one way or the other...deadly sick or just very sick and it didn't get sick at all so the bit wasn't from a rabid animal.
Yes, you are obsessing. But if you don't believe any of us here, call your public health department and ask them. They are the ones who treat this and keep track of it. The incubation period for a human is as short as 10 days but can be up to a year so there is no way to make you feel completely safe as the incubation period is so long. But the fact that the dog is fine after a month should tell you there was no rabies to start with.
If a rabid animal had bitten the dog, the dog would have almost immediately licked the area. Let's say he then nipped you with the rabid saliva in his mouth. He would have gotten rabies to some extent, within 10 days. If he hadn't had his shots, he would be dead in a matter of days or even hours. If he had had his shots, he would still get very sick without a rabies booster from the vet...they still need more shots to boost the immunity. Now the dog didn't get sick at all and even tested negative for rabies so he didn't have it in any form. So whatever bit him, no matter when he licked your hand or nipped your finger, you can't get rabies as he wasn't bitten by a rabid animal.
If we can't convince you, call public health. There is nothing more we can say...it there.