There are a few ways to heal in F.I.S.T Forged in Shadow Torch. The first is by finding a terminal when exploring the world. By interacting with a terminal, you can select Repair. This will health your Rayton to full, no matter how close you are to death. Repair is completely free, so do not hesitate to use it as often as possible.
You will also find little pods that you can destroy on your travels, and inside may be a health vial that will instantly restore your health.
Another way to heal is by using Carrot Juice. You unlock the use of this method of healing by saving Wang from a couple of Iron Legion soldiers. By destroying these soldiers, Wang will be saved, and as well as unlocked an underground door for you to carry on the story with, he'll also give you Carrot Juice.
Carrot Juice will restore a small amount of health, but it can be upgraded to restore more health and have more uses. Drinking this liquid will consume one of the two uses it has, so once both uses are gone. You cannot heal by this method, but they will be restored upon using Repair at a terminal. Think of the Carrot Juice as Estus Flasks from Dark Souls.
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