The past few days I have had a pain in what seems to be a lymph node on the right left of my neck just before the jawline. Today I was looking at my teeth and my two rear molars (not wisdom teeth they were removed years ago) are black. It is on both sides of my mouth and only on the outside (cheekside). Its the entire tooth from the center of it down to the gum and the tooth on the left appears to be turning grey. The tooth on the right has a silver filling in it from years back but thats the only cavity i've ever had and short of the wisdom teeth removal i've never had any other problems. I am a 29 year old male, any idea what may be going on?