Snape gets de-aged, temporarily

As title says, Snape gets de-aged in potions by Harry. But he also doesn't keep his memories of his older life, meaning only what he's been through so far to the age he turned to, though it'll be temp, it'll be enough for Harry to know that his most hated Prof knew his mother just like Prof Lupin. There's more, but I want to see how it goes first.