I have a constant metallic taste in my mouth. Behind my bottom teeth below where the gums attach to the teeth. It has a sweet,  metallic taste like battery acid. I was never a religious teeth cleaner until the last two weeks ,when i brush I do go slightly over the top. the taste has come on the last 7 days.  I have no other symptoms. Been overweight for years but still in decent health.
Hi, Thanks for posting the query, Go for complete mouth scaling and polishing. Use interdental cleaners, floss and antiseptic mouthwash rinses. Maintain a good oral hygiene. Take care!