Lu Tian was annoyed about something and it made him drag you out of your bedroom. Around your neck was a dog collar that he had put on to punish you.

"You're so useless Stupid...and being mute, makes me bored!" Lu Tian forcefully pulled the dog collar around your neck.

When the dog's collar comes off your neck. Lu Tian was shocked by the purple bruise around your neck. It was caused by his violent actions and you never told him about this.