Brief Answer:
Carried possible causes described below.

Detailed Answer:
Hi Rhodes erik2,
Thanks for the query. I understand your concern.
Sence of taste is catched/carried to brain to perceive the information , by taste buds&olfactory nerves(sence of smell)...Any disturbance in the path can cause metalic taste in mouth.Persistant metalic taste in mouth since a month could be from following possibilities.
-Damage/inflammation of taste buds...could be from -tongue... teeth or gums being affected &damaged( bad oral hygiene,smoking or dehydration/drugs like antibiotics taken for infections,allergies,certain blood pressure medicines, radiation therapy)
-Bacterial or viral infections (sinus infection/oral.. tongue or gingival infection/ ear .. nose throat infection /bowel infections &infestations ) can damage the taste buds & destroy normal oral flora to cause vitamin defeciency .
- vitamin Bcomplex,vitamin D &zink deficiencies may result in it.
- food allergies can cause the symptom.
- Surgery of nose,ear or throat /trauma to these parts can damage the nerve endings.
-Stroke or bells palasy can damage central nerves for sence of taste.
* An extensive examination & needful investigations to judge the basic cause &get it removed by specific treatment is the way out of this problem.
The expert to be consulted would be ENT specialist to start with referral to by otolaryngiologist or dentist according to basic cause.
I hope that answers your query. Any follow up query is welcome.
Thanks

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