only reason your lips would turn black is if your messin with res and your makin res balls cuz your outta herb or the res from a joint or blunt get on your lips i remember one nite i was fucked up and i was scrapin all my bowls out and i had a big shit ball of res and forgot that i was using my fingers to sculpt the ball of res and it got on my lips but then again its not really black its more like a brown color