Why did Casey have scars in Split?

Related questions

1. Is split a prequel to glass?
2. Does split mean half?
3. Should you watch split before glass?
4. Is split rated R?
5. Is Kevin from Split in unbreakable?
6. Should you watch unbreakable before split?
7. What happened to Kevin split?
8. What do you mean split?
9. What is split half reliability?
10. What are Kevin Wendell crumb personalities?

Tags

1. #casey
2. #struggle
3. #their
4. #cutting
5. #earlier
6. #scars
7. #being
8. #years
9. #confirmed
10. #caused
11. #final
12. #uncle
13. #stomach
14. #abused
15. #ripped
16. #however
17. #picture
18. #shirt
19. #revealed
20. #inflicted
21. #repeatedly