I called the emergency out of hours vet, who instructed me to keep him under observation, a little swelling was normal and as long as his mouth remained pink and he didn't swell anymore, he would be okay in a few days, but keep monitoring him.
By morning, Whippet Boy had swelled up even more. His gums were bright red and inflamed. He was not eating and lacking in energy. I called the vet again and arranged an immediate consultation.
Whippet Boy's favourite vet was on emergency duty.
"What happened to you"? He asked my dog after seeing how swollen his face was, even without examination.
Whippet Boy was gently popped on the examination table and the vet inspected his mouth and sting site. He was given a shot of antihistamine and some antibiotics to avoid infection of his nasal passages and throat.
My dog had also peed on his front legs, another sign of pain and disorientation.
I've been instructed to let him rest and keep monitoring him for the rest of the day and if the swelling hasn't come down considerably, he will need another shot of antihistamine tomorrow.
My vet assured me I had done the right thing, by seeking out of hours vetinary assistance for a dog who was so clearly unwell.
Meanwhile I am very glad I have pet insurance. It has paid for itself for this year, with this emergency out of hours visit and his recent ear infection and annual immunisation!