If she already has tons of serums and creams, go for something really specific that she'd probably never splurge on herself - like a good premium retinol, an expensive facial oil type of elixir, or even a gadget like a sonic cleanser or facial massager. Those are the things we want but think are too expensive to drop money on, you know? And they're usually way more useful than another generic cream.
Another cool option is a themed kit but actually curated - like a vitamin C set with sunscreen and follow-up guidance, or a treatment ritual with specialized masks (clay, sheet masks from a reputable brand, stuff like that). Big brands like Augustinus Bader, La Mer, or even Drunk Elephant usually have gorgeous kits that look like actual gifts. The upside is everything comes together and wrapped up so it feels fancy 📦
Honestly, check in with her about what she needs right now - like if her skin's feeling more sensitive, if she wants something more aggressive anti-aging, or if she's in an intense hydration phase. A super specific gift that actually solves a problem she's dealing with is way more valuable than a pretty kit that might not be what she needs at that moment!