Final answer:
Mild traumatic brain injury symptoms from a concussion generally last for a few days and heal on their own.
Step-by-step explanation:
The duration of mild traumatic brain injury symptoms can vary. Generally, mild symptoms from a concussion, which is the mildest and most common type of brain injury, last for a few days and heal on their own. However, it is important to note that each individual and injury is unique, so the duration may vary for different people.