What I have found is that in larger injections over 1cc in areas like delt and tri's, some of it will run out the muscle and sit under the skin, even when you pull the needle out (23G) it will run out the hole. The result is red rash at the site, and itchy. Use a 1.5 pin in the quad and if it stays in its fine.
Yes, my injection site is itchy for about 3 days, lol.I know some do and also have itching reaction sometimes ..