Feels Like Vomiting And Severe Intense Burning Running Through Veins Up To Brain. What's Wrong?
You seem to have had a bad episode of hot flush to start with, but the other symptoms of excessive salivation and intense nausea with swollen hands and rest of the body suggests a bad episode of severe reflux disease and angioedema.
It fits with a severe allergic reaction and most likely related to something you had eaten a few hours ago or the last medication at night.
It would help to know if you have any food allergies or suspect you have after reading this answer. You may have had a minor episode to the suspecting food before but not given much of a thought.
The other option is a drug allergy and common medications taken at night before bed are (1) blood pressure pills, some of them can cause bad swellings; (2) cholesterol lowering agents such as statins, that can trigger bad urticaria (hot flush, itchy hives) and angioedema.
With your medical history of hypothyroidism, you will be on replacement thyroxine, so if yo have recently increased your dose, palpitations and hot flushs can be due to excessive thyroxine.
The usual medication for PCOS is metformin, and if you have taken more than usual, a sudden drop in glucose levels can trigger some of the symptoms you had.
I hope the answer has been detailed and look forward for any queries that you may have.
Thanks.