I don't remember much but I think it was a oneshot, or at least just a few chapters. The girl is wearing glasses and looks nerdy and she went into a shop/library and I'm not sure but I think she saw a book/videogame of her crush and basically she can control him using that for a few days.

But after a few days, she failed to return it and she became one of the videogame too.

Please tell me if anyone had read this 😅 and the title too, thank you.

Found it. It's called Kokoro Rental.