If your child is alert, moving normally and responsive to you, then it's most likely a mild injury and you can follow up with your child's doctor in a day or two. It's ok to let them sleep
/nap at this point if they are tired. If your child worsens, however, then that would be a reason to go to the emergency room.
Other reasons to seek emergency care are:
-changes in behavior such as increasing irritability or fussiness
-worsening coordination such as trouble walking
-changes in pupils such as one larger than the other
-lasting or recurrent dizziness
-blood or fluid coming from the nose or ears
- large bumps or bruises on areas other than the forehead - especially in infants
a good rule of thumb is when in doubt, get it checked out!
legal disclaimer: I am providing this general and basic information as a public service and my response to this question does not constitute a doctor-patient relationship. For any additional information, advice, or specific concerns, please speak with your own physician. The information provided is current as of the date of the answer entry.