I'm confused. "The ER concluded that I had a minor head injury, but insisted I did not have a concussion" If not a concussion, what kind of head injury do they suspect, a bruise to the skin ?

The tingling is often due to soft tissue damage to the surface nerves at and around the impact site. Those nerve can take quite a while to heal since the injury is usually to the myelin sheath and it heals slowly. B vitamins help the myelin sheath heal.

Anxiety usually makes everything worse as it causes one to hyper-focus on minute details that were easily ignored before. It does not sound like you have anything serious to worry about.