It is probably a dermatitis. If he is a drooler, then it can certainly cause the skin to get irritated. Why is he drooling? Is there a bad tooth, a growth in the mouth, or irritation to the tongue?
THe dermatitis can be treated with a topical steroid creme or a shot of steroids and the use of antibiotics. It may clear up for a short time,but if the drooling problem isnot attended to, there will be a recurrence.
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Dr. Louis Gotthelf
Animal Hospital of Montgomery
Pet Skin and Ear Clinic