You should take the animal to a veterinary medicine professional immediately. The injury is not life-threatening, but it does risk infection and enduring quality of life issues.
If it is bleeding you need to take your dog to a vet ASAP. Either way he will need to visit a vet to ensure he is ok but take him to an emergency vet if there is any bleeding.
Does the dog have an ear infection? I would suggest to have the vet do a culture on it. Maybe change the dog's diet to make sure it's not allergic to something. Anything you do chose to do consult your local vet first.
Not much you can do except comfort your pet. There may be some fluid discharge which should be wiped clean to avoid it seeping back into your dog's ear.
