Is it necessary to read "kiss me lier" before reading "kiss me if you can"?

I didn't read the spin off but after quick look at chapter 1 I don't think you must read the main story. At most you just miss some backstory but not something that make you don't understand the plot

nah, it’s not necessary. They’re set in the same universe but are completely different stories, so you won’t miss anything just some small details at most

Thanks guys!!