Final answer:
Calmly reassure the father and suggest seeking medical attention for the child to ensure there are no serious underlying issues from the head injury.
Step-by-step explanation:
The correct action to take would be to calmly reassure the father and suggest seeking medical attention for the child, as a hematoma on the forehead caused by a blow to the head could signify more serious underlying issues.
Immediate application of ice may be helpful to reduce swelling, but in the case of head injuries, it is crucial to have a professional evaluation to rule out any complications like internal bleeding, especially around the pterion. Hematomas in toddlers are not uncommon, but due to the potential severity associated with head injuries, they should not be ignored, and saying they will heal on their own can be misleading without proper assessment.