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Hello from JustAnswer.
It would be very unusual for a trunk lid to cause brain injury or internal bleeding if it strikes the head in a situation such as you describe. The headache can occur from the trauma to the soft tissue of the skin and subcutaneous tissue. If you apply ice to the area of the trauma and it helps to ease the headache, that is further evidence that the headache is from the superficial tissue.
However, it is reasonable to be concerned after any head trauma. If the headache is more severe or persistent or if you are having any associated symptoms, such as nausea, vomiting, or any symptom related to the nerve system, such as blurred vision or confusion, it would be appropriate to be seen.
Since this happened this morning, it would be OK for you to go to sleep if the headache is not severe and you are not having any other worrisome symptoms.
If I can provide any additional information, please let me know.
Please let me know if I can provide any further assistance.