My very back molar on my left side is severely damaged. It broke about 5 years ago and the inside and the side facing my tongue is completely gone below the gum line with a cavity. The last 4 days I have been in extreme pain including all the bottom teeth on that side, my jaw, ear, neck and head. The four bottom teeth in front of that one have a red line running across the top, it looks like a vein. What is it? I do not have dental insurance but I have some Keflex last and have been taking it along with Motrin for the pain. It's extremely hard to chew or even swallow and I can't chew on that side at all. Thanks for your time!