I have a couple of characters who had the misfortune of encountering a clay golem and getting cursed with Curse Wound. The wording is clear that treat wounds or overnight rest isn't going to help and any spells will have to counteract the curse before being effective. One of the players is insisting that potions are both magic and not spells, so they should work without having to roll. Luckily we were at the end of the session anyway, so I have time to do some research.
I am leaning towards allowing it to bypass the roll, but it does seem to violate the spirit of the curse. Potions aren't clearly spells in a bottle anymore and there is no requirement to use a Heal spell to make a potion.
Cursed Wound (divine, curse, necromancy) A creature hit by the clay golem’s fist must succeed at a DC 29 Fortitude save or be cursed until healed to its maximum HP. The cursed creature can’t regain HP except via magic, and anyone casting a spell to heal the creature must succeed at a DC 29 counteract check or the healing has no effect. The golem’s counteract level is equal to its creature level.