Thanks for the query
The most common cause for metallic taste
in the mouth is anti biotic therapy and iron therapy since you did not give any history of taking these I will assume you are not on them.
The second most common cause for metallic taste in the mouth is Vit b 12 and Zinc deficiency
. Please approach a physician and get your Vit b12 levels tested.
It is quite possible that you are infected with tape worms too since you were in close contact with a dog who had tape worm infestation. Please reach out to a physician and de worm yourself.