Rash at injection site

After my 6th shot, I got a rash at my injection site. It showed up on the second day and was mildly itchy. The itching went away in a few days but the area (about the size of a quarter) is still a bit red. Has anyone had this issue, and if so, how long did it take to go away? I alternate injection sites every week so I never use the same spot or area twice.