He was wearing a back brace on February 12 at his fan meeting. Fans found out after requesting to see his abs, when he responded, "I have back pains because I over-exercised, so I have a back brace on." He also could not bend down properly.
On the injury concern, his agency told TV Report, "He has back pains. However, he's getting better."
Hopefully, he hasn't hurt his back too severely and gets better soon!