The answer can be simple or very complex.
If the BB just struck the skin of the neck, you may have some bruising and pain.
If the BB went through the skin, there may be other complications: infection from a foreign body is possible. Also, damage to other structures is a concern. The neck has several important structures in close proximity - the trachea, carotid arteries, and spinal cord/vertebral column are all within about a hands-breadth of each other. A BB piercing through any of these structures can be life threatening and you should seek care immediately.
If you are a youngster, you need to tell your parents- NOW. You will need to see a doctor, and get the BB removed. It is really not a big deal- unless you leave the BB in there. If you do that, there is a very good chance that the wound will get infected. THAT is a VERY big deal, and can cause serious health problems. By the way, waiting to tell your folks does not make it better- but waiting WILL make it worse. Go. Talk. Now. Yeah, it is not easy- but you need to do this. Really. So stop reading, and go.
It depends on the size of the bb. If it's a .177 caliber then it will most likely pass through. if it's larger then it depends on the size.
stomach explodes
she would have to stay there for every food she ate
Nothing
Nothing would happen. You would just get a lot of calcium.
Nothing good!
You die.
YOu die
They would probably throw it up...they could die, also if this person was still alive that would be incredible to begin with
you would eat fish
it would survive
If you ate human poo, (which you shouldn't) you would most likely get very sick.
They would run a considerable risk of suffering poor health due to malnutrition.