Within the Souls universe, the only way to heal is to collect and equip unique flask consumables. In Elden Ring, you can collect and use Sacred Flasks or Flask of Crimson Tears, which is equivalent to the Dark Souls’ Estus Flasks. The same applies to Nightreign as well, but you need to explore certain locations to collect more flasks for healing. This guide will explain how to get more flasks in Nightreign.
How to Get More Flasks in Nightreign

There are a few ways you can get more flasks, and one of the more common methods is to find Churches around the map. Anytime you spawn into a match, you can locate 3 Churches that appear randomly( which is what we have recommended as one of the first things to do when you start Nightreign). Interacting with the altar inside the church will give you an additional flask use, which adds on to the already available 3 Flasks at hand. Churches are marked on the map, so have a look after you spawn in and get to these areas first.
There is a way to unlock a fourth church, and that is to start the Shifting Earth: Crater event. This event unlocks if you have defeated a Nightlord or the third day end boss. Since this event occurs randomly, you might have to play for a while till you can find a fourth Church marker appearing on your map. Another way to get an extra flask is to defeat the boss that appears in the evening of Day 2. You can get an extra Flask charge this way.
How to Upgrade and Restore Flasks

Besides this, you can upgrade your flask’s consumption by hunting down all named bosses. Through a random chance, you might get a special reward section called Dormant Power. Within this section, you can select a special buff from the list that appears, and the Improved Flask HP Restoration boosts the HP that you receive from consuming these flasks by a certain amount.
The chances of this buff appearing is random, so you might have to defeat a couple of named bosses before you can get this option. As for restoring your flask’s consumption, the same rules from Elden Ring apply here as well. Visit any Site of Grace and your flask will be automatically replenished.