Bumped my head on outside mirror of truck raising up from picking up a cup that had rolled underneath truck.small cut but headache comes and goes all ?

Concussion: This is most likely soft tissue bruising (contusion) however if you are experiencing intense headaches, you may be suffering from a concussion. See a doctor as soon as possible who can assess for concussion and rule out an intracranial bleed

See MD: Please see your MD ASAP in the ER at your age I am concerned for a bleed and you need to make sure your tetanus is updated.