As far as I understand, the power of the Black Panther is gained by drinking the potion, not by wearing the suit, and that power is responsible for the near immortality and full regeneration of the body, which makes the Black Panther so powerful.
This explains for example how T'Challa fully healed after being near death and frozen in the snow.
Killmonger's wound from the spear did not heal even though he had the full powers of the Black Panther, since he drank the potion, and thus he died.
How is this explained? The sonic dampeners in the railway are blocking the power of the suits, made of Vibranium, not the powers of the Black Panther, so this can't explain it. So what do I miss?