Tweety, I can't answer your specific questions because I don't take insulin. I do know that cortisone will raise the blood sugar. If it's just one shot, it will have a lingering effect for almost a week as it diminishes - I think
but I'm not sure. The other factor is the shot might not be as much as you'd get in a hip or shoulder, so maybe the cortisone dosage is less. I'm just guessing. Maybe you will need to test more frequently to know how to adjust it? I hope someone else can jump in here and answer your question. Good luck.