Headlice!!

I know this is an odd question (or maybe not!) and possibly not the right forum but I am new to this site so apologies if so. My 6 yr old has headlice. The problem I have is she is very head sensitive. I have trested her with full marks and attempted a comb through with much screaming and upset, but i am not convinced I have got them all. Any advice? Doing whilst asleep isn't possible. Products that kill everything maybe? 

I would much appreciate any thoughts Undecided