The boys of 2AM had worked hard to perfect their two-days Christmas concert that was held at the Jamsil Student Gymnasium. They did dance covers of Wonder Girls and KARA’s songs while Jo Kwon did a solo performance, a parody of Britney Spears‘ “Till the World Ends“.

Apparently, the determined leader had worked a little bit too much as he shared a photo of his bruised knees, covered with spots of black and blue clearly visible. The tweet that came with the photo reads, “Goodness.. it just ended~.” Another tweet came from the idol, saying, “I’m so glad I was able to deliver a successful performance of Jo-ritney Kwon-pears, but my bruises.. T_T My neck won’t turn and my hips won’t either.. Ahhh.”

Jo Kwon might have overworked himself during the practice for their performance to reach perfection to get all those painful bruises on his knees. Fans and netizens alike were pained by looking at the photo.

Ouch.