Definitely looks like it could be. You could try giving him an antihistamine first to see if it calms it (if it's an allergy rash). Thought my pup had an ear infection a week ago because he was shaking his head so much. Took him to the vet to find out it was just allergies. Gave him a zyrtec and he was fine.
If it persists, it could definitely be ringworm. It's actually not difficult to treat at home. In the past, I've used a half and half solution of water and apple cider vinegar. Use a cotton ball to wipe down the affected area three times a day. Of course be careful not to get it in the urethra. Also wash down any bedding and his toys once now and again after about a week.
If you're not comfortable treating it yourself or you start treating it and it does not improve, then a vet visit would be in order.