I had a dental cleaning three days ago and it left a metallic taste in my mouth that won't go away. they used an ultrasonic scaler. that was the first time they used one on me. wi'll this metallic taste good away? what can i do about it?

The ultrasonic scaler usage should not be resulting in a metallic taste. Metallic taste can be caused by so many different factors. Were any cavities noted?

Metallic taste in the mouth is probably through the gum bleeding during cleaning. Since you have not done cleaning In a while, you may have swollen bleeding gum or severe gingivitis.

Ultrasonic scaler will not cause metallic taste. If your gums were inflamed, if there was any tarter below the gum line, there may have been some bleeding as corrections are achieved. This is especially true if you were overdue for a cleaning, if you don't floss daily, or if you don't brush 2 full minutes by the clock 2x/day. Bleeding will result in a coppery taste.