"Well, I'd have come to you before I got gangrene," Harry said, a little bit offended. "I did come to you, let's not forget."
Snape's dark gaze didn't leave Harry's face. "Are you qualified to judge the severity of an infection? Are you aware that sepsis can cause its victims to become irrational? You might think you didn't need help when in fact you did."
"I think by the time my arm was rotting off I'd have figured it out!"
"I think that by then it might be too late to save the arm!" Snape glanced down. "Were you aware that you'd already developed an infection?"
"Just a little one. It was under control--"
"And so we come back to your extensive training in the art of mediwizardry," said Snape dryly. "I expect you're oblivious to this, but last night you were running a low-grade fever. And that's not the only danger you've been courting. What about actual poisoning, another possible result of inserting foreign objects into your bloodstream?"
Harry didn't like the way this was going. He hadn't done anything all that dangerous. "Listen, I've had loads worse cuts and scrapes than that and no one even blinked. You're going on as if any little drop of blood could be my death and we both know that's not true! Besides, is it any wonder I might feel the need to make myself stronger? Maybe I'm sick and tired of everyone acting like I'm some delicate flower! Not to mention incompetent!"
Snape's voice went gruff. "You are far from incompetent, Harry. Someday the world will know as much--"
"Oh, great. Like I want more acclaim!"
"Now you're just being difficult." Snape sighed. "Harry, you may have thought you were getting stronger, but what you were doing was in fact serving to weaken you physically. Even if the infection never truly became dangerous, don't you think it could have affected your control of magic when casting? What if you began to accidentally channel magic through your wand and you ended up causing injury to someone? Isn't that exactly what led to your self-doubts in the first place?"
Good point. Feeling himself flushing, Harry concentrated on blowing on his hot chocolate. He kept expecting his father to say something else, but it seemed like Snape was determined to make Harry reply before they moved on. Finally, Harry looked up through his fringe. "I hadn't thought of something like that happening," he murmured.
"Obviously."
"I'm sorry. Is that what you want to hear?"
Snape sighed. "I'm not trying to make you feel guilty, Harry. I'm just trying to make you understand that even such an innocuous injury as pinpricks can have consequences. And I assume it goes without saying that the larger needle you used most recently, was simply beyond reckless."
Harry started to nod, but this time it seemed like Snape wasn't waiting for a reply.
"You could have severed a vein with that implement, you idiot child. As it was, you delved too deeply for a topical salve to completely reach. I shudder to think of the consequences had you developed an infection that deep within your arm. And even aside from infection, the injuries themselves could still cause harm to your magic flow and your ability to defend yourself physically."
Another factor he hadn't considered. Harry swallowed his cocoa abruptly.
"Imagine the disadvantage you'd have been at if, whilst wandering the halls alone, one of your less moral schoolmates had decided to attack you. What if someone had grabbed one of your arms or twisted your wrist to make you drop your wand Ö."
"I don't really need my wand."
Snape gave him an impatient glance. "I do believe I've noticed that. But casting without it would have given away the important advantage of secrecy. We'd once again have been forced to Obliviate all the witnesses, risking the Board of Governors sacking and expelling everyone involved should anyone find out."
Harry frowned. His father was making him feel just awful about what he'd done, but what was even worse was the fact that the worse he felt, the more his arms itched. He knew in his mind that using a needle ever again was a terrible idea, and yet there was a little part of him that wanted one all the more because of it.
He certainly didn't want to admit what was happening, but his father had made him promise to tell him if he had such impulses. He squeezed the mug in his hands, willing the heat to be enough chase away the desire for pain and blood. It also served to keep his hands from shaking. "Dad, I'm not trying to weasel out of this lecture. Honest, I'm not. I know you're right and all, but when you make me feel bad, I start to . . . er . . ."
He didn't need to finish because his father deftly plucked the mug from his hand and pulled Harry into an embrace, holding him close and tight. The itching in Harry's arms subsided slightly. If he pretended hard enough, he could tell himself that it was just his sleeves feeling scratchy. Sighing, Harry relaxed and just enjoyed the feeling of being loved.
Snape didn't speak, not for a long moment. Then, his voice low, he resumed their discussion.
"You're feeling an urge to hurt yourself again." The simple statement was etched with sadness.
Harry nodded against his father's chest. "You said to tell you."
"Yes." Harry felt his head being patted, and then his back stroked. He felt a bit like a baby, being treated that way. But it felt good. Really good, so he didn't complain.
After a few moments more, though, he reminded himself that he was sixteen, after all. Sighing, Harry pulled back a little bit. "Thanks."
His father seemed reluctant to let him go. "I suppose this is why we need the good doctor's assistance. I'm doing the best I can for you, Harry, but in this I seem to have failed."
He didn't want to make his father feel bad, he really didn't. "You haven't failed, exactly. It's just that this is all new to you, right? You never planned to be a father. And even if you had, our problems are just bizarre compared to the ones normal families have. Even wizard families. I mean, how many parents have to think about hiding wandless magic or being prepared for constant attack? I know you've done your best, but you can't think of everything."
Snape's lips twisted. "I do try. To do otherwise would be less than Slytherin. But this . . . no, I don't believe I could have anticipated that you'd turn towards self-injury. Not when you'd never done so in the past, despite all your various traumas."
Harry nodded. "I'm not defending what I did with the needles, but you can't blame me for not worrying about it making me weaker. That never bothered you before when we were training in Devon. I just looked at it as more of the same."
The Potions Master stiffened as he held his son. "Yes, you mentioned as much last night. The analogy is flawed, however. You've been hurting yourself intentionally of late. Your injuries out in Devon, however, were an indirect result of our activities. The goal was to improve your Defence skills. Surely you understood that."
Harry had. "I knew you weren't trying to hurt me, sure. But the needle thing . . . well, I had a goal there too, you know. Get over my fears. I thought if my arms got too bad I could . . . uh, you know, nick some salve somehow, since the healing spells weren't working."
Snape made a disgusted noise. "Obviously you understood the consequences of your training in Devon even less than I'd thought. You learned absolutely nothing."
Harry frowned. "I learned that Wizarding Family Services likes to stick its nose in, so we can't let there be any evidence of . . . Oh, shite. I didn't think about how this might look if they'd found out."
Snape's drawl sent shivers down Harry's spine. "Indeed. I dare say we'd have another lovely notation on our record."
"I'm sorry--"
His father shrugged off the apology. "In any case, I wasn't referring to the authorities when I mentioned consequences. Cast your mind back to Devon. Can you recall the reason why I didn't do more to treat your injuries after our duels?"