Ring Worm Pictures Weird Ring On Dog??

Weird Ring on dog?? - ring worm pictures

My dog has a strange ring in his leg. My vet is closed for the weekend, so I can not see. But I make an appointment first Tuesday. It works quite well. I noticed that Yesturday. It's like a ring. I saw, but the picture ring worm found no similarity with what is in his leg. Ideas?