The reason for Éponine's long absence from Grantaire's flat was indeed that she was hiding her bruises from him. Just as Montparnasse predicted, her father had quite the beating in store for her at home. Bruises do heal, however — even bruises from as vicious a beating as the one Éponine received — and within a fortnight, she was back at Grantaire's door. When he opened it to her, his face convulsed terribly. And for a moment, she thought he was angry. Then he teetered forward and fell onto her shoulder. His body sagged and she caught him, supporting his weight with her thin, spindly arms. He was weeping. She held him as he shook against her.
"Éponine," he sobbed, again and again. "Éponine."
"It's alright," she breathed, running her fingers through his hair. Evidently, he hadn't washed it in days. "I'm here, 'Taire. I'm sorry."
Later, when Éponine told him how she'd bargained for his life with Montparnasse, using her own life as the stakes, Grantaire didn't know how to feel. Perhaps he couldn't feel anymore. Perhaps he was maxed out.
"I'm relieved," she admitted to him, scrubbing a hand over her face in an exhausted manner. "It was the only thing I could think of, but I didn't know if it would work. I knew 'Parnasse was a jealous bastard, but I didn't know he actually cared about me, y'know?" Éponine stared off to the side for a moment, a contemplative expression on her face. Then her mouth twisted into a curious grin and she barked out a laugh. "Why, I reckon 'Parnasse must actually be in love with me! It's kind of nice. I mean, he's a monster, and 'course I'd rather it be Monsieur Marius. But even so, it's nice to have someone love you."
"Montparnasse doesn't love you."
Éponine's smile faltered.
Grantaire's eyes and voice were hollow, but he held her gaze steadily. "If he loved you, he wouldn't hurt you."
Éponine pursed her lips for a moment, then shrugged. "It's more complicated than that, 'Taire."
"No. It isn't."