Is it dangerous if my dog licked up some bacon grease from the pan?

A single small lick is unlikely to cause harm, but bacon and its grease are very high in salt and fat, which are problematic for dogs. Regular consumption, even in small amounts, can lead to pancreatitis, obesity, and other health issues. For this one-time minor exposure, just watch for signs of vomiting, diarrhea, or a tender abdomen over the next day or two. If your dog seems unwell or ate a significant amount, a call to your vet is a good idea.