As long as there is external visible injury ie swelling on the head, baby needs to be examined urgently, to rule out internal injury.
For head injury, 1st hour is the golden hour!!
Next Steps
if there are danger signs like fall from a height over 1.5 meter, loss of consciousness, persistent vomiting, sleepiness or altered behaviour, etc: you need to call ambulance for immediate assistance.
Health Tips
It is foolhardy to take advise for such situations online, as baby needs to be checked in full, especially for other injuries.