I tear my heart open, I sew myself shut,My weakness is that I care too much,And my scars remind me that the past is real,I tear my heart open just to feel.
Loki has always had issues with being close to people; it means opening up to them and allowing them access to his most raw self. It was why he always seems so quick to recoil from his own feelings, retreating into a hardened, stoic shell in order to mask his pain. Even while imprisoned, he was reluctant to so speak before anyone; his tongue had blunted and grown clumsy in his captivity.
The trickster's most painful memory; the one he finds always reminds him of how cruel and shallow the Aesir are, is when he was held down by those he once considered friends while dwarfs pulled twine through his lips. His lips sewn together messily, he had stumbled in agony and fear; his weapon had been stripped from him by force. The violation of his most prized asset still serves as a reminder of why he should only ever allow Sigyn to see his wounds, to know his failings and to know his fears.