Unfortunately it's just how it is these days. It's perfectly normal/acceptable for girls this age to want the make up and skin care that is blasted all over social media.
I don't think this is something to beat Lou down about. We don't know what they bought and it's not dissimilar to my childhood obsession with bubble baths and makeup in the 80s or the fact all my babysitting money was spent in Boots and The Body Shop in the 90s, the only difference now is the marketing is specifically aimed at young girls.
Not all young girls are going to be into this kind of thing of course, but a lot are and it's a tale as old as time, playing at being teenagers.
I do feel sometimes they can't do right for doing wrong by us on this thread.
(I do find Lou annoying generally BTW

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