Glad you got an answer it sounds like what Bugsy had - it did heal quickly once we started the antibiotic.
You may want to add a spoon of 'live' plain yogurt to his diet - at least 2 hours after you give the antibiotic - it helps keep things happy inside!
Wow Snickers is a HUGE gsp - I've seen one over 80lbs! If you could see Bugsy in person you'd see more similarity. His eyes in particular, ears, nose (not his snout so much), tail (not docked) and of course his energy LOL
People that know the breed and people that know him are quick to suggest gsp/great dane mix. He was supposed to be a lab mix but people that know labs and really look at him and watch him (like me) can't see any lab in him.
Did you realize that Snickers would be so big?