The arm is probably red and swollen after shooting up because the body is rejecting the drug that was injected. It could also be an allergic reaction to the drug. Another reason could be that an artery was hit. The only way to know for sure is to seek the advice of a physician.
You should get in to the doctor as soon as possible if it has not resolved in 30 minutes. Also, it could be an infection.
If you have a swollen hand and it's red after shooting up, this could possibly mean you blew a vein. It could also mean that you have an infection.
Go to a doctor or hospital immediately!
If its like a bubble on your arm you were probably bit by a gnat or mosquito. If your whole arm is swollen you could have an allergic reaction or a bee or wasp stung you so you should see a doctor
Pain
There are a variety of reasons your cat's paws are swollen and red. Some of these include an insect bite, or infection.
your arm went to sleep or it is numb
Some individuals notice a shooting pain which goes from the wrist up the arm, or down into the hand and fingers.
Enjoy your early, slow and agonising death. :)
It may be broken--please get to a doctor as soon as possible.
i play basketball and if the person with the ball goes up for the shot and you slap him on the arm it is a shooting foul and you go to line to shoot free throws
See a doctor.