Lmfao
His friends came over previously and tidied up his whole apartment, I'm assuming they changed his sheets too.
I stand corrected, I reread the chapter and Mokyeon's friends came over before he slit his wrist, but a few days pass between his suicide attempt to him passing out drunk in the parking lot. He goes outside Nanjo's workplace and he's wearing different outfits, meaning different days pass. He also bandaged his wrist and it became a scar. During all of those days I'm assuming he had the time to change the sheets lol
convenient his lil suicide attempt is suddenly crisp and white and not an ominous brown/red stain on his bed