Poor Jens!

Vaccine reactions are actually fairly common in dogs, so you're definitely not alone. Basically from now on, your vet will probably give him a little bit of diphenhydramine (Benadryl) either mixed in with the shot or about 20 minutes prior to giving the shots and then have you give Bendaryl at home later. Luckily it's very easily treatable. One thing to consider is that once he's got all his puppy shots, his 6-month parvo booster and his first set of "adult" vaccines at one year - it may be worth it to run titers. The vaccines we have for Parvo and Distemper are very good and if your pup has a normal immune system, he may not have to be vaccinated yearly to stay protected. It's definitely something to talk about with your veterinarian. His reaction to the vaccines shouldn't worsen with age, but just so he doesn't have to have his face swollen up, it might be worth the extra cost.

HTH.