Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services for severe breathing difficulty, choking with inability to speak or cough effectively, blue or gray skin, fainting, seizure, severe confusion, or inability to wake.
If several people in the same space develop headache, dizziness, nausea, or confusion, leave the area and treat possible carbon monoxide exposure as an emergency.
And for anyone, someone who:
Seek prompt medical care if coughing begins after swallowing liquid candle fuel, even if the person initially appeared well.
Also seek care for repeated vomiting, increasing abdominal pain, fever, wheezing, unusual drowsiness, persistent eye pain, vision changes, or a worsening burn.
Arrange routine medical follow-up if mild stomach symptoms continue, a skin reaction does not improve, or candle fragrances repeatedly trigger headaches, coughing, or asthma symptoms.
A clinician can help identify practical ways to reduce future exposure.
The article also says
A person who remains well after a small taste of ordinary wax may only need home observation after consultation with poison control.
Follow the specialist's instructions about food, fluids, and how long to watch for symptoms.
To prevent another exposure, store candles, fuel refills, fragrance oils, and wax melts in their original containers and out of children's reach.
Never transfer lamp oil into a drink bottle or food container.
Use candles on stable, heat-resistant surfaces, keep them away from anything that can burn, and extinguish them before leaving the room or going to sleep.
Every sign above is quoted from the sofidex article on Candles poisoning. If you are not sure, err upward — it is always reasonable to be checked.