How to Unlock Bartender! Refill! Achievement
One of the buildings you can unlock in the camp, the Herbalist’s Hut, will allow you to use potions to heal yourself during expeditions. Once you unlock the Herbalist’s Hut, you will unlock this one soon after. Potions are drink automatically when your HP drops below a certain threshold, so you just need to keep playing (and loosing health) until you drink 50 of them.