The Medic feat (from Unearthed Arcana: Feats for Skills) has the following description:
During a short rest, you can clean and bind the wounds of up to six willing beasts and humanoids. Make a DC 15 Wisdom (Medicine) check for each creature. On a success, if a creature spends a Hit Die during this rest, that creature can forgo the roll and instead regain the maximum number of hit points the die can restore. A creature can do so only once per rest, regardless of how many Hit Dice it spends.
Can a creature benefit from this feat for multiple hit dice?
Example: I short rest, and someone with the Medic feat binds my wounds. I use 3 Hit Die of d10 (Fighter).
Do I recover 30 HP, or only 10+2d10?