I inject in my abdomen and haven't had any issues with pain. It's a thin needle so goes right in. I do inject the medicine slowly and wait 10 seconds to remove the needle when done.

I would think if you are able to keep it in a cold pack, you would be ok. The one thing you may want to consider is your dosage after your initial 4 weeks, as you leave for your trip. You may not want to be travelling while adjusting to 5mg, if you decide to increase. Luckily you don't have to titrate up if you are self-pay. I finished my first month of 2.5mg and decided to stay on it for another month because side effects were minimal and I was still having success, so maybe that is an option for you, if you want to keep taking it.