Reduce swelling and redness after a flu shot
Today I got vaccinated against flu (influenza). After a few hours, the puncture site is very swollen and reddened. Even movements of the arm have hurt.
I cooled the injection site with a "cool pack" from the fridge and after a few hours the area was painless and not hot anymore.
I can remember that it took 2-3 days for vaccinations in the years before, until the injection site was pain-insensitive. This was faster and more effective with the cooling pack.
This method also alleviates the symptoms of other vaccinations.