Friends tell me what's wrong?

Hey grow friend. It’s really hard to say when you don’t give us much back story. But just based on this picture the red stems indicate to me probably a strong LED presence in your garden. So I would up it on the cal/mag and I suspect your leaves are a little magnesium deficient. But without knowing your substrate, watering/feeding regimen at what PH. It’s hard to give you a better answer. You’re in flowering cycle so I would up the P and K a bit all at a balanced PH for your medium and maintain conditions and she should definitely pull through. Cheers 🤙