yeah i being having the same question since chapter one like yo her mother been using it since SO LONG
That'd be counterproductive to the plot if that was possible. And if it was true anyways i'd be very disappointed at the mangaka.
I actually think it would pose a very interesting problem. SInce Kasane's whole existence is about stealing others' appearances, it would be a crisis if the lipstick runs out
Bam she'll just kill herself. It's pretty simple.
Maybe when it runs out, that is the last face she can have until she too succumbs to death and a new one is mysteriously made for her child.
I like that sci-fi thought
What if the lip stick stick runs out?