I don't know about a love potion, but I've found Social Bunny super helpful in shifting the affections of a fellow teen. My teenager kept spamming her crush with flirty messages and finally the pink bar went up and then he was more receptive to her romantic overtures and now they are romantic partners.
But just trying to talk to him in person, he kept disliking her attempts to turn their friendship romantic. I think one of his romantic turn offs might be the flirting category, which makes it hard to build the romance up from nothing, but Social Bunny did it for her instead.
