Thanks for your question.
Your symptoms are concerning and require immediate consultation with a doctor preferably in the ER. Please do no delay. The dizziness and nausea may be due to the late development of symptoms of a concussion itself.
These symptoms could also be due to post-concussion syndrome. For this you need to consult a doctor and have a physical and neurological examination. This syndrome has a good prognosis and majority of patients recover within 3 months.
You need assessment by a doctor for brain injury and imagining studies with further management if indicated.
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