How do you get blessings from Aryth's Spire?

I'm not sure what exactly it's called, but I think you're talking about the boosts you can get to help with fighting, right?

When you're exploring that zone, you'll occasionally discover a bottle of potion or something similar. You can choose to drink or ignore the potion. If you drink, there's a chance you'll get a boost to regain health, improve magical/physical damage, or improve magical/physical mitigation (defence). There's also a chance the potion will explode causing a lot of damage to your party. Which boost or explosion you get is up to chance.

Thank you. I was wondering what it was when that potion showed up.