Final answer:
Surgery is most likely needed for severe nerve injuries, as mild or moderate injuries can often heal with non-surgical treatments and temporary injuries typically resolve on their own.
Step-by-step explanation:
Surgery will probably be necessary to fix a severe nerve injury. When it comes to nerve damage, the severity dictates the course of treatment. Mild injuries often heal with rest and conservative treatments such as physical therapy. Moderate injuries might need more intervention, but are not always severe enough to require surgery. However, severe nerve injuries usually do not heal on their own and can result in loss of sensation or function in the affected area. Surgery may be necessary to repair the nerve and restore function. Temporary injuries, on the other hand, typically resolve themselves without the need for surgical intervention.