cheek black spot

I started using a new toothbrush and may have brushed a touch hard.  Later the left side of my mouth where I have a bridge was inflamed and it looked like my gum had colapsed where the false tooth on the bridge was.  Above that high on the gum is very tender to the touch and constantly sore.  That I understand but I also found a large black spot on the same cheek way back almost behind my last molars.  One of  my caps back there is half porcelain and half metal (silver?). Could this be causing the black spot even though the metallic side of the crown is facing my tongue?

[Jerome Tsang, DDS]

How is your hygiene in the bridge area?  Do you use a floss threader or some instrument to get underneath the bridge to keep the area clean?  You may need to see your dentist for a check up and cleaning in that area.

As for the black spot near the gum, it is possible due to the crown.  The metal margin of the crown could show through the gums and give it a black/metal appearance at the gumline.