B.;
I am not sure if even natural Tea Tree oils would even assist if there is a bad break out?
I have heard / read that once you have an infestation, you need to replace your bedding as this is one place they sleep. Also, you need to check out the floor boards, night stand, dresser, and any other furniture in the room of the infestation.
As for the itching, this is the time when I do recommend going into your doctor. (Also, check your little girl!)
Whenever you travel, it is VERY wise to make sure before you bring in your suitcases (or if you have to have them with you to put them in the bathroom on the tile); YOU check the mattresses, backboards (they come up easy enough) and floorboards. You can also see tell-tale signs sometimes on the walls.
I recommend doing an internet search on them, you will find your answers.