My Boston terrier.....

I have a Boston Terrier/Apple Head Chihuahua mix and my dog gets pink under his neck because we pet him there alot and his hair has thinned under his chin.

Mine also had a red faced i think it was because of mange, but now i got him to a vet and we are treating him. Thankfully the redness is starting to get away. But i think yours could be just allergies. Try to feed him hypoallergenic foods instead.

I've read that Boston's sometimes get red faced if they run around or get excited. If you are concerned, you should check with your vet. Also check for info on Boston's online. Because they are a pure bred dog, they are more likely to have certain problems. Mine had bad knees and needed three operations. She also wound up with Cushing's disease, which is common among Bostons. You also need to be careful of their eyes. Since they 'bug out' somewhat, they can be easily scratched, especially if the dog is playing with an excited dog. They can also have some breathing fits, which in part comes from their short snout. The shortened snout also makes them likely to snore.

My cousin had a Boston terrier that got a very red face every now and then. That was because of allergies, he was allergic to lots of weird stuff, things you can find in dust or food.