if you get restrain potion from merchant and finish "More potion" directly, then you can't learn how to make restrain potion. And you can't start the quest of lizard's part
The recipe for the Restrain Potion is Red Berry, Nut, Nothing, Nut, Red Berry.
Strong Restrain Potion is Red Pulp, Nut, Earth Moss, Nut, Red Pulp (not sure which one you need).
Either way, once you make a potion, it should unlock the recipe for it if you don't already have it. It will also make a quick shortcut for it once you've successfully made the potion 4 times.