The backs of your arms works but I need help doing that.

You can inject in any fatty area. Lean people have less options

I give it in the hips and thighs. However, I have hit the muscle in my thighs a time or two, and it really hurt. When I have hit a muscle it also left a lump for quite a while.

I give it in the thighs and hips

I'm a retired nurse and we would give insulin in the fatty part in the back of the arm.