We all know what happens. You tell the doctor, who insists that vaccines are perfectly safe,that the reaction is a coincidence, that you're imagining the reaction, you're over-reacting, and anyway, vaccines don't do that.
Imagine if peanut allergy sufferers were treated the same way:
Mother: He just ate his first peanut butter sandwich, and suddenly, his lips and face swelled up, and he couldn't breathe!
Doctor: Calm down, don't jump to hysterical conclusions. Correlation does not equal causation. It was genetics. Or coincidence. Or both. But it had nothing to do with the peanut butter!
Mother: But we have peanut allergies on both sides of the family!
Doctor: Nonsense! We know peanuts don't cause allergies, because the peanut industry has kindly provided us with their own studies, done on kids with no family history or other risk of peanut allergy. They funded, directed, interpreted, and marketed fourteen different studies, and THEY say that peanuts don't cause allergies. You let little Timmy eat all the peanut butter sandwiches he wants, and I'll write prescriptions for the swelling, choking, vomiting, etc. If he has trouble focusing on schoolwork while he's choking, we'll give him Ritalin, too. And I'll write you a prescription for an anti-depressant for you, because you are getting hysterical.