OMIGOSH! Pistol had that exact same injury! In the same spot! I never did figure out what he did it on, there had been a storm and he was in the field. The next morning is when we found it, too late for stitches. I remember there was a spot that was so deep I could put my entire pinky in it. I will see if I can find a pic of his scar. It isn't bad at all really. It sweats which is funny in the summer, he has a stream of sweat that comes from it....
It looks yucky bad but keep doing what you are doing.