Narcissistic, neurotic people are capable of making sudden foolish decisions about personal grooming. Remember when Britney Spears shaved off all her hair?

One day Justin wakes up, looks at his eyebrows and thinks “oh my gosh they look way too similar to my real father”, so he goes ahead and plucks them all out. So then he looks like a freak. So his make up artist has to paste on fake eyebrows to cover up the fact that he pulled his real eyebrows off.

TLDR: Justin probably over plucked his eyebrows and then his make up artist had to paste some fake ones back on to cover up that bad decision.