Harry wanted to tell Draco that Severus had been an unfair bully who wouldn't allow a child to learn in his classroom, but at hearing Draco's fond tones for the other man, he let the protest die in his throat. And things did change when Harry had learned the truth about it all. He just hoped that Teddy had the same fondness for him when he was older. He sighed and looked out at the two boys kicking a ball back and forth.
His attention snapped to Draco when he mentioned the horrible night when Harry had found Draco in the lavatory, and proceeded to use a spell he had no idea the consequences of. "Are they... are they awful?" He swallowed and looked at Draco with a very concerned look in his eye. "I know I never said it then, but I'm sorry. I'm so very sorry. It was foolish of me to try a spell I didn't know."
He sat for a moment, "It was Snape's spell. All it said was 'for enemies'. It was in the book, and I was curious about what it would do... I'm sorry it was you at the other end of the spell."