Eschar

noun

1. A superficial structure of dead tissue, usually hardened, commonly, but not necessarily dark, adhering to underlying living or necrotic tissue, caused by gangrene or a burn
2. (loose or obsolete) Any hard, dark, commonly flattened or sunken lesion or crust, especially on a burn, abscess, infection, wound; commonly a coagulation of blood or exudations, not necessarily involving dead or necrotic tissue.
3. (figurative or literary) The emotional imprint of a trauma such as grief, loss, or degradation