About 5 hours ago, I administered a dose of the Spectra 7 vaccine (7-in-one) into the loose skin on the back of Duke's neck. I've administered this vaccine before on my previous pup as I like to keep up on shots, however, I just noticed the area where I gave the shot on Duke appears to be a tad swollen, and it is a bit swollen to the touch. When administered Duke didn't even budge or cry. My previous pup didn't have this kind of reaction and he did whimper. I'm just curious to know if this is a common side effect that goes away with time ? He's not itching at it and it doesn't appear to be causing him any pain, but it is somewhat noticeable as his owner. Any input would be appreciated.