A lot of bites have some localized tissue damage, whether caused by toxins produced by the venomous animal's genome or resident bacteria in their venom glands (

A lot of bites have some localized tissue damage, whether caused by toxins produced by the venomous animal's genome or resident bacteria in their venom glands (aside from bacteria getting into the wound separately, causing some amount of necrosis). Concentration matters, and I haven't seen anything indicating that necrosis is a real problem in black widow bites like it can can be from recluse venom (allegedly) or flesh-eating bacteria. Also, the claim in that (Chinese) paper of necrotic venom isn't well sourced.