Thank you for posting your query.
First of all, I would like to reassure you that there is no cause of concern based on your symptoms.
The bump is likely to be a small scalp hematoma
(collection of blood in the soft tissues over the skull bone). This would resolve on its own in a few days.
As you said, your symptoms are due to a mild concussion injury
. You can take betahistine
tablets to reduce dizziness
Wishing you good health,
Dr Sudhir Kumar MD DM (Neurology)
Senior Consultant Neurologist