It's difficult for me to say as I self insert my cannulars but they are painless to self insert I find it no different that injecting with a pen or syringe.. The sound of the inserter firing really put me off this method...
But ask the nurse to allow you to insert one into yourself, then you will know what sensation your daughter is likely to feel, then you be able to gauge which might be best way of tackling the first one..
But reasure her that it only has to be done every 2-3 days depending on which you use, or if you have a problem and it needs resiting for any reason..
The only non-allergic thing I can think of to numb the area, is a good old fashioned icecube, in a poly bag so that the area is kept dry!