| I understand your concern, and I don't mean to be unkind, but why in the world would you ask a bunch of mostly untrained (myself included) pet owners who can't even see your dog?
Take him to the vet - not only for the health of your dog, but for your own peace of mind. The possibilities are numerous, and most of them probably aren't that bad.
If you haven't already, this would be a good time to develop a relationship with a vet. This is essential to to health, happiness and longevity of your friend. (I once asked our vet, and I was only half-kidding, if he would consider being our family doctor.) | 
