In those twelve hours, they had a similar conversation to this one multiple times and it always ended the same – whenever Hermione wanted to treat the runes on his back, he would answer with a growl, pulling her body closer to his; whenever she tried to get out of bed and do something else, like cook food for him, or make more healing potions that they were beginning run out of, or send a Patronus to Hogwarts to make sure everything was in order there, he would immediately get up to follow her, so she had to stay in bed if she wanted him to lay there too and heal properly.