pf2e.fyi
From Pathfinder Lost Omens Ancestry Guide, which isn't enabled.

Salt Wound

REACTION
Activity reaction

Frequency once per day
Trigger A creature that has blood and is not at its maximum Hit Points hits you with a melee Strike

Effect You channel salt and brine from your blood into the creature's wounds. The creature must attempt a Fortitude using your class DC or spell DC, whichever is higher. On a failure, the creature takes 1d6 persistent acid damage and is Sickened 1 by the pain. On a critical failure, it instead takes 2d6 persistent acid damage and is Sickened 2.
Pathfinder Lost Omens Ancestry GuideOGL