Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Any suspected swallowing of ethylene glycol is an emergency, even if there are no symptoms.
Contact emergency services and a poison centre immediately.
In the United States, Poison Help can be reached at 1-800-222-1222 .
Elsewhere, use your local poison information service.
Call emergency services immediately if the person is confused, very sleepy, having a seizure, breathing abnormally, collapsing, or difficult to wake.
If the ingestion may have been intentional, do not leave the person alone while help is being arranged.
Routine follow-up is different from emergency care.
And for anyone, someone who:
Do not wait to see whether the person becomes ill.
Do not make them vomit, and do not give food, alcohol, or another home remedy unless a poison specialist specifically instructs you to do so.
Take the product container or a clear photograph of its label to the hospital if this can be done safely.
Breathing symptoms after a significant vapour or mist exposure also need urgent assessment.
After hospital discharge, attend planned blood tests and kidney checks.
Seek earlier review if urination decreases, swelling develops, vomiting returns, or new nerve symptoms appear.
The article also says
For skin or eye contact, remove contaminated clothing and rinse the affected area with plenty of lukewarm water.
Contact a poison centre for advice based on the product and length of exposure.
Every sign above is quoted from the sofidex article on Ethylene glycol poisoning. If you are not sure, err upward — it is always reasonable to be checked.