They never really had a relationship, she said yes to prom on the episode titled "pictures of you", than on the next episode they were in a classroom making out, Shelly's fellow clean teen members see the two exiting the room and she freaks out and says they can't be together, than she sleeps with Mouth and after says they can't be together and prom is off and tells him never to contact her, and the last time they see eachother is the season finale at Rachels party where he punches a guy for calling Shelly a slut and pretty much end of story.
