He chased a rabbit while on his lead and got yoinked once he hit the end of his rope, which gave him kind of a bump or blister, then his collar just rubbed on it till this. We switched to a prong collar and it seems to be healing, vet says puppy was being a puppy and just needs to rest from his normal collar for a while.
Good to hear and yikes thats a nasty mark.
My dog wears a regular collar, with tags, license and a tracker.
When I take him out, i always use the prong collar like you have there with his leash attached.
That way if something ever happens and he gets loose from the leash:
if the prongs pop off, or the leach connection comes off, or the leash breaks etc,
then he still has his normal collar on. for when someone finds him.
He should heal fast. He's a great looking puppy. Glad he's gonna be OK.