Been relaxing for decades and never tried washing the day after touchup because always understood that the chemical needed a few days to "take". This may be yet another "myth" regarding black hair (like the grease thing, yikes!). I always wait at least 3 days before washing out of extreme caution -- don't want to "undo" my do, especially after the time and money spent. Perhaps I should debunk the myth and try washing day after to see what happens. I dislike that faint chemical smell after each touchup . . .
BTW, 4b relaxed.