I would strongly recommend that you see your doctor
. This is a worrisome symptom. If you feel a decline or worsening symptom, this may even require an emergent visit to the emergency room.
To state the obvious, the brain is a vital organ. It works through a combination of sophisticated interactions on the mechanical and electrical level. Any small damage can cause significant problems with various motor, thought, sensory or language function.
You are describing a verbal paraphasic error -- which is when one word is substituted for another. This requires evaluation.
You should be evaluated after any head trauma. While a concussion
is possible, there are other possibilities that are more dangerous. A bleed in the brain is one of the feared complications. For example, a subdural hematoma is when blood slowly builds up around the brain and compresses it. Another possibility is a CONTUSION of the brain -- which is essentially a bruise
of the brain.
A concussion is a diagnosis of exclusion -- which means we have to rule out these other bad symptoms. While it is very possible that this is a symptoms of a concussion that will resolve, this needs to be addressed in order to make sure there are not any other worrisome causes.