When does local reaction end?

I got my 5th injection yesterday but I still get the local reaction. After a few hours from the injection, the injection site gets itchy and swollen. With the first four injections, the time between the injection and reaction got longer but yesterday I got it only few hours after the injection. The itchiness was so bad that it woke me up from my sleep. I put cortison creme on it and itchiness disappears in a few minutes.