I have a couple of vertical lines that are in both upper molars. I don’t have any pain even when I eat, but the craze line, or crack, is big enough that I can feel it with my fingernail. I am concerned that they are there. It’s making me worried to damage them more. Just because I can feel them with my fingernail does that mean they are cracks, or can craze lines also be felt like this. Should I worry?