Our Cursed Love by Julie Abe

Julie Abe's OUR CURSED LOVE is a magical 50 FIRST DATES meets LOVE AND GELATO set in Tokyo, Japan—about destiny, the impact of the choices we make, and the magic of true love.
Six days to remember.
Love or lose him forever.
Remy Kobata has always wished she was destined to be with her best friend, Cam Yasuda. All the way from being neighbors from birth to mixing up magical prank potions together to their "just friends" homecoming date during their senior year in high school, nothing's a secret between Remy and Cam—except for how much she is in love with him.
Remy is trying to work up the courage to confess her feelings during their winter break trip to Japan, when she gets selected for a mystical tea leaves reading and it reveals that they're not meant to be together. After they stumble upon a secret magical apothecary in the back alleys of Tokyo, Remy and Cam are offered an ancient soulmate elixir, created before all love potions were banned by the magical government. They each have their reasons for wanting to take it, but what could go wrong with finding your soulmate a little earlier?
Except, after they drink up, their senior year trip flips into the worst vacation ever: Cam has forgotten who Remy is. If she can't help Cam remember her by midnight New Year's Eve, they'll both be cursed to forget each other. To unravel their past and rewrite the future, Remy and Cam must travel through Tokyo to rediscover Cam's memories and make new ones—and maybe even fall in love all over again.