Bone Dust - (Must upgrade Dah's Cage into a hut first & have done Wenja Welcome quest)
Upgrade it to also unlock the other Udam Skills in Dah's tree.
After upgrading his cage into a hut, go inside and speak to him. He will be having a problem with "Skull Fires" and asks you for an odd quick fix.
He tells you that a big fix is in an Udam camp Far to the east.
Head over to Dah's map marker to the east of the cold northern area.
When you reach the area, find the Udam camp.
You can simply use your owl to scout the area and look for the healer. The healer is highlighted in red.
You can still use the owl to tail her if you want. The healer will simply go into her hut and you'd have to get the bone dust inside.
You can either kill everyone in the camp or go in the hut, find the bone dust, and run out the camp. Inside the hut, there are skulls with something in them. One of them will have bone dust so inspect them all. Enabling hunter vision highlights them in red and they have smoke coming out of them.
After you have obtained the bone dust, Get out of the camp to complete the mission.