If you think you have ringworm on your tongue, you need to see a doctor. Ringworm is a fungal infection, and it can not live on mucous membranes, such as those inside the mouth. You can spot ringworm because it is characterized by an itchy, red circular rash. Inside the rash, there is a healthy-looking skin. The name ringworm comes from the way it looks under your skin. There is not an actual worm under your skin, it is just a fungal infection.