I have personally met several persons who have experienced delayed or missed diagnoses of venomous spider bites here in the Greater Rochester area. While similar conditions, not treated with antibiotics immediately, offer far more serious consequences, the consequences of a missed or delayed diagnosis of venomous spider bite can also have a serious effect on life, health, and quality of life. Especially in cases of tissue necrosis, in which cultures return negative for any serious bacterial infection, testing for the presence of venom ought to be seriously considered.
Long after creating this page, I have come to understand that the spider in question is actually Loxosceles rufescens, the Mediterranean recluse spider. It has much the same appearance, and possesses a similar necrotizing venom. Recent changes in human behavior have also permitted the spider to take up new residences in some cases. Areas which have seen infrequent use during Covid-19 may need to be investigated for spider inhabitance before resuming normal activities.
I am not a medical professional. Any such wound should be examined and diagnosed by trained medical personnel. If you suspect that you are experiencing such a medical condition, seek medical treatment immediately.