Can a regular MRI scan without contrast of the neck show damage arteries or torn arteries?

Potentially. Mri of the vessels in the neck can potentially show dissection in aneurysm without administration of contrast. Often the two techniques, that is with and without contrast techniques, are used together.
Not optimal but. Sometimes, especially large vessels with significant damage/dissection can be detected by mri. Mra (mr angiography) is much better at imaging the flow of blood in arteries and veins, but can miss subtle damage to the vessel walls. Cta can be very good at looking at the vessels and the anatomy around them, especially in cases of trauma.