I always was puzzled by the weird rituals canines performed around plastic fire hydrants.
Did the vet examine the dog? Did they show you how to pull the prepuce back over the penis with some k-y? Keep a close eye on this and keep your vet informed, please.
It is under the dash on the diverside ,were u put the changge.
Have the Vet check for peas its a term used for small amounts of dirt, and fluid that builds-up in the sheath. My Mothers's ShiTzu had the same problem, and it was bad enough he required surgery. Does he urinate ok? I'd take him to another Vet for a second opinion, maybe one who specializes in small dogs.
Put salt on it, seriously