Suggest Treatment For Bruise With Black Spots On Foot

I have a bruise-like appearance on my foot with a black spot in the middle; it does not hurt or itch. I now have one on my hand; the bruise is fading, but I can still see the black spot. Help, I have no idea what this is. I am a 64 year old woman, about 5'4" and 176 lbs. I have ulcerative colitis and recently had a severe extraction of a bad tooth that was in there too long.