Snape let out a heavy breath through his nose, "I cannot stress the importance of you reinforcing those shields, Potter," he said seriously, and for the first time possibly ever, Harry didn’t feel like the Potion’s Professor was looking down his nose at him, "They are your mind’s only defence against unwanted attack or intrusion - do you understand?" Harry nodded silently, "Good - you may leave. Continue administering the dittany as I instructed you, and I will see you again about this matter in a month or so," Harry noticed that he didn’t comment on the improvement, or as he already knew, the lack of improvement of the state of his neck, "I believe Mister Malfoy is waiting for you in the corridor, despite my instruction," he finished dryly, turning his back on Harry in a clear dismissal. 