How long does a black fly bite last for?

A black fly bite typically causes localized redness, swelling, and itching that can last from a few hours to several days, depending on the individual's reaction to the bite. In some cases, symptoms may persist longer, especially if there is an allergic reaction. Generally, the discomfort tends to subside within 1 to 3 days. If symptoms worsen or persist, seeking medical advice is recommended.