Again the real issue is that no amount of HP damage causes a wound that affects the character's
- ability to walk or run
- ability to attack with weapons
- ability to cast spells
- ability to make STR, DEX or CON saves
- ability to make INT WIS or CHA saves
- ability to see or hear
- ability to manipulate objects with the hands or feet
- ability to dodge
So no matter what the damage dealt until it is the last one, its a minor wound.
No if you want to make injuries a CORE rule, fine. But if no wounds are serious enough to cause injury, then HP loss is mostly fatigue, luck, and scratches. A night of bed rest should recover fatigue, resync luck, shrink bumps, and scab up little cuts.
5e is nice enough to make it take 2 days (a weekend) to get back all HP and HD.
Again, the point of old D&D editions slow healing was not to represent realstic wounds healing. It was to
keep you from playing the same PC every week so you didn't get attached and didn't mind PCs having wide differences in power. This wayy you didn't complain about your PC ranndomly dying or your friend getting rolling a OP paladin.