Thomas,
It sounds like you've got the new dog companion jitters... Every dog I've ever had, did this to some extent. It shows up more in white dogs than in darker dogs and white show dogs worry about staining. (They make a commercial product to wipe the stain off the fur, too.) Barker the Elder has 1 tear duct in each eye that is blocked which may make this worse. Tear production can be affected by irritation (such as that caused by allergies.)
So your vet, I think, is right...
It sounds like you've got the new dog companion jitters... Every dog I've ever had, did this to some extent. It shows up more in white dogs than in darker dogs and white show dogs worry about staining. (They make a commercial product to wipe the stain off the fur, too.) Barker the Elder has 1 tear duct in each eye that is blocked which may make this worse. Tear production can be affected by irritation (such as that caused by allergies.)
So your vet, I think, is right...