Healing in D20 games isn't super intuitive and may be needing to think of mroe as "battle fatigue" rather than actual bloody wounds. The games themselves hint at this, especially how easy it is to regain hit points, but it's not clearly stated all the time.
In my view, hit points quite literally represent your battle-readiness and only when it fits the narrative is an actual physical wound. More often than not it's a strike that imbalances the player's character and makes it less battle-ready. Meanwhile, especially for monster it's often quite literally it's wounds abstracted, and losing a chunk of hit points is akin to a real wound. A lot of the time even for player's characters, the narrative may refer to lost hit points as wounds and still allowing the character to regain a large amount of hit points fairly easily.
Homebrew house rules for dealing with this can be found below.
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