"A week," he said and rubbed the back of his neck. "You were bitten by those big spiders Hagrid was making us take care of. Padma was too, but you had some sort of reaction. I don't know, I didn't understand what Pomfrey was trying to tell me."
It wasn't Ron's fault. He knew Hermione would have questions and he had tried to understand, but it was impossible. Pomfrey had used big words he didn't understand.