What is skin inside your mouth called?

The skin inside your mouth is called the oral mucosa. It is continuous with the skin on the outside of your body at the vermilion border of the lips. The lining of the oral cavity consists of stratified squamous epithelium (similar to epidermis), which sits atop a connective tissue layer known as the lamina propria. The oral mucosa is a thin, moist membrane that lines the inside of the mouth and is composed of several layers of cells. The top layer of cells is called the epithelium, and it is made up of squamous cells that are tightly packed together. The epithelium rests on a layer of connective tissue called the lamina propria, which contains blood vessels, nerves, and glands. The oral mucosa is also home to a variety of microorganisms, including bacteria, viruses, and fungi.