My dog, a poodle, had the same thing happen to her on the back of her neck just below her head. I took her to the vet who gave me a cream to put on it, but it just got bigger. When I took her back to the vet, she said, we have to operate which she did. I don't know exactly what it was because the vet didn't explain it well to me. She thought somethng had bitten her and she scratched it, but I don't think it was that. When I came to pick my dog up the next day, she had a three inch incision and lots of stiches where the hole had been. The hole was the size of a half dollar and almost an inch deep. I put a scarf around her neck besides the big collar she had to wear while the incision healed which took about ten days. She's fine and the scar is not visible and she is just fine now. It was very weird to have a hole just pop up in her all by itself. I find it hard to believe that she dug a hole in her neck with her nails. It was frightening, but all is well now. Take your dog to a vet this minute. It won't heal by itself or any cream. I did have to give my dog antibiotics after the surgery and put salve on the stitches. Take care of your dog now.
New to this so I’m not sure how to reply properly but I have a question: do you have a tie out for your dog? Back in 2017 my GSD was on a “pig tail” tie out (looks like a cork screw that twists into the ground so you can attach a leash to it. She took off running after a rabbit and pig tail dislodged from the ground and spring back hitting her leg, creating an almost same exact mark (picture below) it took a while to heal but I put antibiotic ointment on it and kept it wrapped
