I’m so sorry that happened! Luckily, since your dog caused the scratch, chances are it doesn’t go down into the sheet metal, which makes it easy to fix without the help of a professional. In most cases, some touch-up paint will take care of the problem. You should be able to find the correct color at an auto parts store or with the automaker or dealership.
Best of luck with the repairs, and with trimming your pup’s nails!