I have unfortunately caught lice from DD. I found a large one, so I did a chemical treatment to kill everything quickly and since then I'm keeping my hair well oiled and combing regularly. The total number of lice I have combed out is 4 - the big one, and 3 miniscule ones. While I hope I got the infestation at the beginning fine-combing thick calf-length hair gives the lice plenty of time to get away from the comb and my head itches horribly, so I'd like to know if anyone knows

- do lice have some kind of chemical in their saliva which makes the bite itch afterwards or does it only itch when you are bitten?
- how long does the itching last after the lice are dead/removed from the hair?

I'm also prepared to accept the fact that the itching is at least partially due to the fact my scalp is massively oversaturated with oil, and that the comb has scratched my scalp but I'm going to carry on with the oiling and combing for another week just to make sure I've really got rid of them.