Glossitis
Glossitis is a condition in which your tongue gets inflamed with changes in shape and color. This makes it swollen, red, and painful. In some cases, your tongue might also look smooth with tiny bumps on the surface. All of these can be an early symptom of vitamin B12 deficiency. In addition to causing pain, this health issue would also change how you speak and eat. You can also experience some other oral problems, such as itching mouth or mouth ulcers. [5]
