Thank you for your query on Healthcare Magic,
The bump due to the contusion
developed due to the formation of hematoma
because of bleeding and accumulation of blood in scalp
The bump may reappear if there is any another trauma over it again.
But vomitings, altered behavoir and bleeding frome nose or ear to be watched and to be reported immediately.
Consultation with your doctor is essential to examine the swelling and nervous system.
Hope I have answered your query.