Every time you get knocked to 0 hp, con save with DC = damage taken from the blow that knocked you down. Fail and I roll on the table.
1 Lose an Eye. You have disadvantage on Wisdom
(Perception) checks that rely on sight and on
ranged attack rolls. Magic such as the regenerate
spell can restore the lost eye. If you have no eyes
left after sustaining this injury, you're blinded.
2 Lose an Arm or a Hand. You can no longer hold
anything with two hands, and you can hold only a
single object at a time. Magic such as the regenerate
spell can restore the lost appendage.
3 Lose a Foot or Leg. Your speed on foot is halved,
and you must use a cane or crutch to move unless
you have a peg leg or other prosthesis. You fall
prone after using the Dash action. You have
disadvantage on Dexterity checks made to balance.
Magic such as the regenerate spell can restore the
4 Limp. Your speed on foot is reduced by 5 feet. You
must make a DC 10 Dexterity saving throw after
using the Dash action. If you fail the save, you fall
prone. Magical healing removes the limp.
5-7 Internal Injury. Whenever you attempt an action
in combat, you must make a DC 15 Constitution
saving throw. On a failed save, you lose your action
and can't use reactions until the start of your next
turn. The injury heals if you receive magical healing
or if you spend ten days doing nothing but resting.
8-10 Broken Ribs. This has the same effect as Internal
Injury above, except that the save DC is 10.
11-13 Horrible Scar. You are disfigured to the extent that
the wound can't be easily concealed . You have
disadvantage on Charisma (Persuasion) checks
and advantage on Charisma (Intimidation) checks.
Magical healing of 6th level or higher, such as heal
and regenerate, removes the scar.
14-16 Festering Wound. Your hit point maximum is
reduced by 1 every 24 hours the wound persists.
If your hit point maximum drops to 0, you die.
The wound heals if you receive magical healing.
Alternatively, someone can tend to the wound and
make a DC 15 Wisdom (Medicine) check once every
24 hours. After ten successes, the wound heals.
17-20 Minor Scar. The scar doesn't have any adverse
effect. Magical healing of 6th level or higher, such
as heal and regenerate, removes the scar.