Used: Barkskin and the Nektaria region

There should be at least 1 merchant in the nektaria region who sells barkskin potions.

Not including the dog.  He cuts you off at level 4, or sooner if you have X amount of GP worth of equipment.

I just ran through every merchant from Vale to Macedone except for 3 (well, technically more, I considered Priscilla's priestly products all one merchant, although it's really 20 merchants, each restricted explicitly to one's deity).  Out of those 25 merchants, 20 sold some sort of potion on a regular basis, and not a single one carried barkskin.

I found that rather odd considering that it's a lowbie level potion, and it would seem more logical to find a lowbie level potion for sale in an area where you'd most likely find lowbies exploring and hunting... More logical to have barkskin potions for sale in the region than some of the other 'specialty' potions readily available.

After the next module update, you'll find that a lonely gnome has built himself a little place at a crossroads on the way to Mistborne.  He'll have stuff a small time wizard would cook up.