"Shhh." Just the way Draco choked out 'Mum' brought tears to Narcissa's eyes, but she held them back. Now was not the time to get emotional. Not when she had to worry about Draco.
Knowing that her son couldn't have consumed very much of the potion in his condition, Narcissa thanked Merlin that she'd had the elf bring several. She was eerily reminded of nights when Lucius had come home, during the First War, from serving the Dark Lord, in a condition like this. That was one of the reasons she had never wanted Draco to get involved with the Dark Lord, or with his followers — she couldn't bear to see her son, her only son, in such agony.
Picking up another healing potion, Narcissa put it to Draco's mouth. "Drink slowly and don't talk, love. Mummy's here. I'll take care of you." When he finished that vial, she would levitate him inside and see if she could heal him, or if he would need to go to St. Mungo's.