I have never got that from site injections before except once when I injected 2c in to my bi and I moved the pin a lot. It was red and hurt for a couple days
Keep an eye on your tri's if there red. After a few tri injections my tri's turned really red and felt hot also. I went to the doctor and found out i had an infection.
the doc said stop injecting ..lol....that aint ever gonna happen! Then she gave me a script for some antibiotics. But my arms were real bad man, my elbows were all swollen , it was nasty. After a few days on the antibiotics it was gone.