@Mariel - IPIR means Immediate Post Injection Reaction. Not fun, usually means you hit a vein.

Okay...I've been injecting C for 3 1/2 years now. Here's what I learned works for me...
First of all, I discontinued injecting in my thighs and my arms. I got gray colored skin, craters and now I have a permanent thickening of the subcutaneous tissue under my thigh skin. My neuro told me to just inject in the hips and abdomen.
I use the autoject set at an 8...it goes in deeper leaving less lumpage...I take a shower beforehand per neuro's instructions and it definitely helped with the pain and swelling. I inject, then put a cottonball over the area and push in for one minute, no rubbing!!

I used to ice the area...it never helped. I find I get very little swelling with this method.

I did get one reaction a couple of months ago. I recommend keeping a journal of these episodes with dates. If you continue to get reactions, it might be time to try another dmd...