On 06.08.2013 at around noon, TOP of BIGBANG was spotted at a hospital in Seoul waiting to get treatment for a disc in his neck. He was due to attend a VIP premier of the movie Hide and Seek at 8PM in Seoul on the 6th of August, but he didn’t attend due to the injury.
It seems that a disc has slipped in his neck, which means he could take 4-6 weeks to recover, and might be in a lot of pain.
In short, a slipped disc is where the disc in between the vertebrae in your spine splits, and the gel comes out. The broken disc will then put pressure onto either your whole spinal cord or just on a single nerve root. This can be extremely painful, and can be treated with either simple physical therapy or surgery (depending on how serious it is).