Helping Hand

choose to increase either your constitution or strength score by one, to a maximum of twenty two.

When a creature you can see is attacked in a nonmagical way, you can take half thee damage (rounded down) as temporary hit points.
If you attack a creature on your turn, take away the temporary hit points and add them to the damage dealt.
If you don't attack a creature on your turn, take away the temporary hit points, and take that much damage.
If you exit combat before your turn, and don't have a chance to attack a creature, take away half of the temporary hit points (rounded down)
and take damage equal to the remaining half.
You cannot use this feat if the damage would reduce you to 0 or less HP.