Thanks for sharing your concern with healthcare magic forum.
Burning sensation can be due to GERD refluxes.Metallic taste
in mouth usually occurs as a result of periconitis due to impacted wisdom tooth
I would suggest you to visit a dentist
and get a thorough clinical evaluation regarding this.
Swish with lukewarm saline frequently.
Usually in such cases,metronidazole
along with analgesics and muscle relaxants has to be administered.
Meanwhile,take a balanced,nutritious diet without starving.
Do not take medicines in empty stomach,keep yourself hydrated.
Hope this helps.