I cannot train my skimmer in the underwater ability without 8 mastery points, and I have only 3. I collected (and spent) all the mastery points in the Path of Fire regions (Crystal Oasis, Desert Highlands, The Desolation, Domain of Vabbi, Elon Riverlands, Domain of Istan, Sandswept Isles, Domain of Kourna, Jahai Bluffs, Thunderhead Peaks, and Dragonfall) and am at a loss as to how I can get more.