I found this info online:
"Vitamin deficiencies. Not getting enough iron can cause sores at the corners of the mouth, the taste buds to become small, or can lead to a sore tongue. In some cases, advanced iron deficiency can lead to anemia and may cause scarring in the throat and esophagus, making swallowing difficult. While vitamin C deficiency causes gums to easily bruise and bleed, deficiency can lead to tooth loss. Vitamin D deficiency boosts risk of jaw fracture and gum disease."
It could be you need vitamin C among others, but what you say sounds scary--good thing that you are going to the dentist right away. In the meantime, have some orange juice.