With the current system of temporary wounds and things that apply to your body, my suggestion is based around buffs using the same mechanics, or at the very least decoration that apply to your body for a time before fading.
War paints and body paints are an iconic part of early cultures & shamanism (something near & dear to hearth magic).
Also Jorb, this would give you a chance to add even MORE swirlies for the mystical H&H aesthetic you've been developing :^P
Body Painting could be a skill bought after discovering Hearth Magic. Or if you don't want to make a new skill, implemented with Hearth Magic possibly.
Each paint would add some kind of temporary buff to attributes or something to that effect -- or again, nothing if just decorative.
Paints would be made via several steps: Querns, Cauldrons, & Clay Jars (this would give more of a use to Clay jars), And obviously there needs to be some type of base material to make these paints.
Here are some ideas for them:
Brown - Boiling Cauldron + ground Walnuts (5 walnuts > ground walnut)
Red - Boiling Cauldron + ground sumac shoots (a new semi-rare bushy foragable, found in "Mediterranean" biome)
Blue - Boiling Cauldron + ground Woad leaves (a new semi-rare foragable, found in the dark-green grass biome with the gads of rocks)
Yellow - Boiling Cauldron + ground Rose hips (5 rose hips > ground rose hips)
Green - Boiling Cauldron + ground Field Blewit Mushroom (a new blah blah blah foragable, found in field biome)
Orange - Boiling Cauldron + ground Alder Bark (a new collectable taken in place of regular tree bark from Alder Trees; 5 bark > 1 ground bark unit)
Purple - Boiling Cauldron + ground Orchella Lichen (foragable from rocky/mountain biomes)
White - Boiling Cauldron + ground Limestone
Black - Boiling Cauldron + ground Charcoal/Lots of Ashes
Each paint paste would fill up a jar, and be able to be used to apply onto a character's face/body. After that, it would last for the time of 1 in-game day, or any other arbitrary time.
Anyway, I hope this isn't way too convoluted, I'd really like to see this implemented.
Thanks for reading & All the best.