When I flew to Indonesia I took a "change" bag for myself and my daughter. So, it had a way for us to "shower" (wet wipes), wash my face (facial cleansing wipes), brush my teeth (disposable tooth brush), stuff for my hair, and an ENTIRE new outfit (undie pants, socks, snazzy sweats, cute t-shirt, sports bra).
We flew from Chicago to Korea (13 hours) and then Korea to Indonesia (9 hours). I "changed" in Seoul and I felt like a million bucks!!!!!!
I would put together something like that for each of them in a smaller bag that she can put inside her carryon. Because all my stuff was wipes, you don't need to pull it out and put it through security.