Why do I have a bad taste in my mouth after scaling?

Hi doctor,

I had a dental examination and scaling done last week. After that, I had a very bad bitter or metallic taste in my mouth when I ate or drank along with a stinging sensation on my tongue. I also had sensitivity in my teeth. The only difference during this visit was an ultrasonic scaler was used, instead of manual scaling. I had never undergone scaling with an ultrasonic scaler before. The scaling was extremely uncomfortable. I had a bad taste in my mouth after scaling. But, it got worse later in the evening when I tried to eat. Could this procedure have caused some nerve damage? Please help me. The next day, I also had a headache and felt nauseous after scaling. The bad taste, stinging sensation of the tongue and tooth sensitivity have worsened badly. I have never experienced these problems after a scaling and a dental examination. I do not have any amalgam fillings. I have a history of sinus infections and TMJ pain.