Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
After swallowing cedar leaf oil, follow the poison center’s or emergency department’s observation instructions.
And for anyone, someone who:
Seek urgent reassessment if coughing, fever, shortness of breath, repeated vomiting, worsening abdominal pain, confusion, unusual movements, or difficulty swallowing develops after going home.
Follow-up instructions are based on the route and severity of exposure.
Someone evaluated after a minor skin or eye exposure may need only continued symptom monitoring.
Persistent redness, pain, rash, tearing, light sensitivity, or blurred vision should be reviewed by a clinician.
Keep all arranged follow-up visits even if symptoms have improved.
Routine follow-up may also include reviewing how the exposure occurred.
Store cedar leaf oil and other essential oils in their original, child-resistant containers, locked away from children and pets.
Do not transfer them into beverage, medicine, or food containers.
Follow label directions for ventilation and protective equipment.
The article also says
People treated for seizures, breathing problems, digestive-tract injury, or abnormal liver or kidney tests may need repeat examinations or laboratory testing.
Every sign above is quoted from the sofidex article on Cedar leaf oil poisoning. If you are not sure, err upward — it is always reasonable to be checked.