Your dog needs to be examined by a veterinarian. It does sound like an allergic reaction. Insect bites can cause swelling of the muzzle, lips, and around the eyes. Dogs typically become itchy. When they start having vomiting, diarrhea, weakness and collapse then they are having a severe reaction called anaphylactic shock. This is a life threatening emergency. Your dog needs to be evaluated then receive injectable Bendaryl and a steroid. You will follow up with oral Benadryl at home--the dose is 1 milligram per pound of body weight by mouth three times a day for 2 days. Do NOT use the Cold and Sinus variety--it needs to be plain Benadryl.
My 11 Month Old Laberdoodle Is Vomiting, Diahrrea, Swollen Ears, Jaws, Snout And Eye,What Could Be Wrong?
It probably got bit by something try some benadryl and see if that works if it don't work then you will want to take it to the vet as soon as possible
He may have an allergic reaction to something