Help me find this bl please

The ml used to go to a martial arts school when he was younger and had a crush on his friend ( lets call him K ) there.
Ml and K got into an accident and someone else got into K's body and K went for mental rehabilitation
K has an increased appetite now and Ml is the only one who knows K's real name and now K and Ml have a crush on each other
K had a close friend in that martial arts class and K told him too about it , K's friend has blue hair