There are numerous types of injuries that can occur in Kingdom Come: Deliverance and you’ll ultimately need to heal yourself periodically throughout the game. This can be done by sleeping, visiting bathhouses, or drinking potions.
While minor afflictions can be cured through these means, there are times when Henry is badly injured and bleeding. This unique injury type requires that you use a bandage as the character may bleed out before making it to somewhere they can be healed.
Unfortunately, you cannot use potions or healing items in combat. If you sustain injuries during a combat sequence you’ll need to see it through. Potions do have an affect over time so you can use them prior to a particularly hard battle or sequence in the game where you need an edge.
Things like Alcohol can give you a boost in different situations as well but does not “heal” your character.