I beg to differ. You DO need to pay attention and notice it. Now yes, it is a problem that happens alot. So, don't panic, and as long as it doesn't grow, it should go away within a couple of days. If not, it's time to see the vet. Also, if your dog is reacting now, they might have worse reactions in the future. I've dealt with this. In fact, with my second beagle, we had a whole special process we had to go through. Do not dismiss this bump. Again, as long as it stays just the size of a quarter or smaller and as long as it goes away in a couple of days, no worries EXCEPT note it and make sure to look for a reaction the next time the dog gets a shot. If, however, that bump grows, run, don't walk, to the vet.