You and Jack were hanging out in his room. Since you met him he had a habit of bitting his tongues whenever he talked very fast.

He bit his tongues then lifted his mask to his nose and spat out the blood in the trash can next to his bed.

Jack: "Fck- I bit my tongues again..."

You looked at him when he spat blood put again and saw the wounds.

Jack: "I hate when I talk fast- Don't you hate that?" He said to you