After a crash, many people notice a headache, but the way it began is easy to overlook. Some headaches build over hours or days, getting a little heavier each time you check on them. Others seem to arrive all at once, as if a switch had flipped. Neither pattern tells you much on its own, but the start is one of the first things a clinician will ask about, and it is easier to describe while it is still fresh.
This article is educational only. It does not explain what a headache means for you, and it cannot replace an exam with a licensed clinician.
What a slow build can look like
A gradual headache often begins as a dull pressure at the back of the head or behind the eyes. You might mistake it for tiredness, a long day in the car, or the glare of an overhead light. Over the next day or two, it may spread, come and go, or settle into a steady ache. Some people find that rest, a dark room, or a cool cloth changes it a little. Others notice no difference at all. Note what you see and when it shifts, rather than deciding what it is.
What a sudden start can look like
A sudden headache can reach its peak within moments. People often describe it as the worst headache they have ever had, or as nothing like any headache they remember. Some notice it along with a stiff neck, nausea, vomiting, confusion, weakness, trouble speaking, changes in vision, or a seizure.
If a headache starts suddenly, or if any of those signs appear, do not wait for a routine appointment. Call emergency services or go to the nearest emergency department now.
Writing down the start
You do not need a special form. A paper notebook or a phone note works. For each headache, write the date and clock time you first noticed it. Then write whether it crept in or came on abruptly. Add a rough strength rating from 0 to 10 that only you can give, and note where it sits: front, back, one side, or both. Record what you were doing when it started, what you had eaten or drunk that day, how you slept, and whether you had taken anything for it.
Keep each entry short, one line if you can. The goal is a clear record you can hand over, not a diary of every feeling. If you have headaches on several days, put a single line under each day so the pattern is easy to see at a glance.
Bringing the note to your visit
Bring the note to your appointment and show it early, before the exam begins. Tell the front desk or your clinician that you want to describe how the headache started, not only how bad it is. Explain whether the headaches have changed since the crash, and whether they have come back after a period of feeling better.
Ask what signs would mean you should go to an emergency department right away, and ask what to do if a headache changes over the coming days. Those questions are worth asking before you leave, while the answers are still clear in your mind.
Why the start matters
A headache that begins slowly and one that begins suddenly raise different questions for the people who examine you. Describing the start gives your clinician a clearer picture of what happened and when, which can guide which parts of the exam to focus on. It also helps you notice a change early. If a headache that was steady begins to escalate, or a new sign appears, that change is worth reporting.
Write the start down today, even if the headache is mild. A short, dated note is one of the simplest tools you can bring to a visit, and it costs nothing to keep.