It wasn't Snape's presence at all. Harry's scar didn't hurt because Severus Snape looked at him. That's the impression he got in the first book, but actually his scar hurt not because Severus was looking at him, but because Voldemort was facing him - as he was inside Quirrel's head.
Harry's scar had hurt during Arrival Feast because of Quirrell's connection to Voldemort; Snape was then talking to Quirrell, allowing Voldemort, from the back of Quirrell's head, to sense Harry's presence.
According to J. K. Rowling during a web chat, the lightning scar no longer burnt or hurt after Voldemort's defeat. J. K. Rowling stated that the pain from Harry's scar on his forehead was caused by the piece of Voldemort's soul trying to leave his body through the wound it entered to rejoin its master's soul.
The pain, coupled by his dreams that seemed to link to Voldemort, started to mean that more than ever Harry's scar was becoming a living link to Lord Voldemort.
I presume that was because at that time, Voldemort didn't hid behind Quirrell's turban. According to Harry Potter and the Philosopher's Stone - the book, Quirrell himself admits that Voldemort had to keep a close watch on him after the failed robbery at Gringotts.
Voldemort was almost in control of Quirrell's body by that time. Voldemort controlled Quirrell as to attack Harry. This activated Lily Potter's magic where Voldemort is not even allowed to touch Harry. And that's why Harry was able to burn Quirrell down.
Originally Answered: Did Snape know that Quirrell was hosting Voldemort? No. Snape did not know Quirrell was hosting Lord Voldemort during the events of Book 1. He tried to stop Quirrell from acquiring the Sorcerer's Stone on Dumbledore's orders.
Voldemort intentionally made six Horcruxes, but when he used Avada Kedavra on Harry, he unintentionally created a seventh Horcrux. Instead of dying, Lily's love for Harry created a counter 'curse' known as Sacrificial Protection and saved Harry.
Yes, he loses his ability to speak Parseltongue. In fact he lost the ability the moment Voldemort destroyed his part of his soul which lived as a horcrux ... And, yes, once the fragment of Voldemort\x27s soul that Harry contained was destroyed by Voldemort, Harry lost the ability to speak Parseltongue.
As Lupin told Harry and the Weasleys by Bill's bedside when they asked why his scars from Greyback wouldn't heal, some scars left by Dark Magic can never be healed. Harry's scar from the Killing Curse is also such a scar.
The most likely reason why Lord Voldemort's nose disappeared and he devolved into such an evil-looking creature is that as he dabbled deeper into the Dark Arts, his appearance gradually became as distorted as what remained of his twisted soul.
Harry got the scar when he was just a baby after Voldemort tried to kill him with a curse, but as his mum Lily tried to save him, it hit the dark lord instead - leaving the young wizard with a mark on his forehead.
The spell, named 'Avada Kedavra', is cast using a hand movement that mimics the zig-zag of a lightning bolt, according to a Harry Potter fan site, which left its mark on Harry's head. The revelation impressed dozens of fellow users, with one writing: 'I actually didn't know that.
In these memories Harry saw Snape's frantic conferences with Dumbledore about the prophecy and how he begged for some way to keep Lily safe from Voldemort; and later, when her death made him wish for his own.
In the first movie the the scene of the troll you can see that snape has a bleeding leg, why? Snape was bitten by Fluffy the three headed dog. When Troll was released, he went to make sure that no one was after the stone as everyone was distracted by the troll.
In the Chamber itself, we see a large statue of a wizard, which Harry presumes is Salazar Slytherin. We also meet Tom Riddle, who is, as it turns out, the heir of Slytherin.
Ron imitates the sounds Harry made while opening the locket in order to open the Chamber of Secrets in that book, but that is not really Parseltongue but rather simple parroting.
As J.K Rowling revealed, Albus Dumbledore had mastered Parseltongue too – although he could not speak it aloud. We're not sure why Albus learnt the language, but perhaps the Hogwarts headmaster wanted a better understanding of Voldemort.
Draco Malfoy's mother Narcissa was cold, cunning and devoted to the Dark Lord. But she was also a mother, which meant she was willing to risk everything to make sure her son was safe. When Harry survived Voldemort's Killing Curse for the second time, Narcissa pretended he was dead so she could get to Draco.
Though Harry encountered many opportunities that deemed Avada Kedavra necessary, it remains as one of the Unforgivable Curses Harry Potter never cast. For one, he viewed the spell as an immoral practice commonly used by users of the Dark Arts.
Voldemort wanted to humiliate Dumbledore, not kill him directly. Plus the story wouldn't allow it, the book would have been over so quickly. Voldemort was a dark lord that could have also been killed MANY times with the killing curse, but what story would there be if that happened?
Defeating The Dark Lord with his signature spell
Disarming is about defence, not murder. Voldemort was a killer, Harry was not. It was an important distinction for Harry, who had learned so much about Voldemort and seen first-hand the ways in which they were similar.
Snape's fierce devotion to and love of his childhood friend Lily, Harry's mother, is the foundation of that loyalty. After Harry Potter and the Half-Blood Prince, Snape's loyalty was a matter of intense debate among the fans.
He doesn't trust Snape as Dumbledore does, but he believes that he can detect any disloyalty. Moreover, Voldemort regards Snape as highly intelligent and therefore ' as a true Slytherin ' a person whose top priority is to take care of himself. To his twisted mind, selfless equals stupid.