Harry screamed when Voldemort touched him because Voldemort had used Harry's blood during his regeneration, which inadvertently bypassed the ancient protective charm that had previously shielded Harry from Voldemort's direct touch. This meant that the unique magical protection derived from his mother's sacrifice was no longer an absolute barrier against Voldemort's physical contact.
The Power of Sacrificial Love: Lily's Protection
For years after his parents' murder, Harry Potter carried a powerful, ancient magic within him – the protection of his mother, Lily Potter's, sacrificial love. This charm was activated when Lily chose to die to save her son from Voldemort, binding a potent magic that repelled the Dark Lord.
- Early Encounters: In their initial confrontations, Voldemort found it agonizing to touch Harry. For instance, in Harry Potter and the Sorcerer's Stone, when Professor Quirrell (possessed by Voldemort) tried to lay hands on Harry, his skin blistered and burned, causing immense pain to Voldemort. This was a clear manifestation of the protection.
- Dumbledore's Insight: Albus Dumbledore later explained that this protection resided within Harry, rooted in his blood, making him immune to Voldemort's touch as long as he could call the Dursleys' home his own, as it was there that his mother's sacrifice was continuously renewed.
Voldemort's Return and the Compromised Protection
The situation drastically changed during the events of Harry Potter and the Goblet of Fire. Voldemort, in his quest to return to full power, orchestrated a ritual involving dark magic, one of the key ingredients of which was Harry's blood.
The Regeneration Ritual
During the eerie graveyard scene, Voldemort's servant, Peter Pettigrew, performed a horrifying ritual to bring the Dark Lord back into a physical body. The incantation required:
- Bone of the father, unknowingly given: Tom Riddle Sr.'s bone.
- Flesh of the servant, willingly given: Peter Pettigrew's hand.
- Blood of the enemy, forcibly taken: Harry Potter's blood.
This last ingredient was the critical turning point. By taking Harry's blood and incorporating it into his new body, Voldemort unwittingly took some of Lily's protective magic into himself.
| Aspect | Before Voldemort's Rebirth (Pre-GoF) | After Voldemort's Rebirth (Post-GoF) |
|---|---|---|
| Protective Charm | Fully Active & Repellent | Compromised, but still present |
| Voldemort's Touch | Agonizing to Voldemort | Painful for Harry |
| Harry's Blood as a Tool | Source of Lily's protection | Used by Voldemort to bypass the charm |
The Scar: A Point of Contact and Pain
When Voldemort, now fully regenerated, touched Harry's forehead and specifically his scar, the pain Harry experienced was immediate and excruciating. The internal reference states that Harry's blood, now part of Voldemort, meant Harry was no longer protected from Voldemort's touch. This act directly proved the compromised protection.
The scar itself was not just a mark; it was a physical remnant of Voldemort's first failed Killing Curse and a direct, albeit unwanted, magical link between the two. When Voldemort touched it, he wasn't just touching Harry's skin; he was touching the very conduit of their unique connection, now made vulnerable by his own choice to incorporate Harry's blood. The scream was a reaction to the intense physical and magical agony of this new, terrifying reality.
This moment signified a new, more dangerous phase in their conflict, where Harry's previous immunity to Voldemort's touch had been effectively neutralized.
