What does "glow-down" mean?

A glow-down is the opposite of a glow-up, meaning it’s when someone appears to be doing worse, either in terms of their looks, lifestyle, or success. 

For example, if someone hasn’t been taking care of themselves, maybe slacking off on their appearance or letting their life become more chaotic, their friends might jokingly say they’re having a glow-down.

The term is often used on social media and it’s not always meant to be mean, but more as a playful observation when things aren’t going as smoothly as before.