Black Myth: Wukong has lots of things in common with the Souls games, and rechargeable healing potions are among them. The Gourd is Wukong’s version of a healing potion, and it gets its charges back every time you rest at a Shrine, but this makes enemies respawn, too.
You need all the healing you can get to progress in Black Myth: Wukong, so you should upgrade your Gourd whenever you have the opportunity. You can upgrade the number of uses or mix in different ingredients to alter the Gourd’s effects, but first, you need to find Shen Monkey in Chapter One.