you can collect the health buff in red arena in Vateshran after you have cleared the Wound (blue arena). For this you have to go thru the would portal and collect within 20s or so the next would thingy, press x and go for the next would thingy until you get to the platform to collect the health buff.
For this you have to cross a lava area and jump from one little island to another. Unfortunately these islands are mostly farther apart than you can jump. I often die there because I have to walk a bit thru lava and my stamina is already low and my potion on cooldown. Is there a trick or so that avoids me hitting the lava here?