If you have a dangerous condition, it will be evident. You will have one or more of the following:
excruciating head ache
a difference between functions on the right side versus your left side
Loss of muscle control
vomiting and extreme nausea
extreme sleepiness
and a few other extreme symptoms or loss of function

If one of these symptoms shows up rapidly, get to the ER.

Otherwise, you have either suffered another generic concussion or caused your previous concussion to be aggravated.

You deal with the symptoms, not a specific diagnosis of cause.