I can only comment on what works for me...
I find that the thighs are a little more sensitive than the stomach...not much but some.
If I let the pen set out for about 30 to 45 minutes then it really helps. the house is never more than 72 to 74 degrees f so there should be no problem.
At first I didn't let it warm up and I iced the area before injecting. That hurt...then I allowed the pens to warm a bit, but I still iced the area....that hurt almost as much. so then I figured the idea was to inject the humira at a temp that was as close to the temp of the body, so I quit icing and it quit hurting for the most part. I also make sure that when I grab the skin where I am injecting, I do so with a very light grab and very little pressure.
there are times when the injection still hurts, but I assume I have hit a small nerve.
because I had a resection done in November and the incision was about 8 inches long straight up the midline I have been injecting mostly in thighs. I did one in the stomach but found that my nerves in that area are still upset from the surgery ( I wll wait at least 8 weeks before I try that again)
For me it has become pretty routine,....I almost laugh now when I think back to all the prep and worry that went into this. I used to lay down and let myself get calm...then my wife would do the honors....then eventually I started doing it...but still it was 15 to 20 minute process with towels, ice packs and stress. NOW.....I letthe stuff sit out, when the timer reminds me that time is up ... I usually walk into the kitchen, turn off the buzzer, roll up my shorts pant leg or pull down the tops if wearing long pants (rare here in Florida) rub with the alcohol wipe, pull the pen apart, lightly grab the skin, place the pen on the skin, pop the button and BINGO all done....other than letting the pen sit out...the whole process now takes less than a minute....just over a minute if you include proper disposal of the pen and wipe.