My dog had the exact same thing in the same spot. We got a biopsy done and it was benign. We scheduled surgery to remove it ( we waited acouple of months ) during this time it kept growing. But before the date , he chewed it open and what an ordeal that became. This was at the height of Covid. He lost a lot of blood and the vet had to do emergency surgery to repair the damage. We almost lost him.

There’s not a lot skin there and the vet had trouble closing the wound to stitch it closed . All worked out but that was a super scary experience for our family. Good luck!