My left upper arm swelled up terribly, bruised, and developed a very hard egg-size knot beside the injection site. Over the egg-size knot area, my skin was red & hot to touch. The circumference of the swelling initially was the size of a small grapefruit. I experienced & continue to experience severe pain and limited range of motion in my left arm. I keep icing the area and keeping an eye on the injury. I have never had a reaction like this before. It wasn’t due to my Pharmacy immunizing tech, he did a wonderful job.