Re: white rings on tongue
It sounds like maybe it's a Geographic Tongue or either Thrush mouth.
The tongue is normally covered with a layer of small bumps (papillae). Geographic tongue results when these projections are missing in certain areas of the tongue. The papillae loss creates smooth, red patches on the tongue, giving it a map-like, or geographic, appearance.
Geographic tongue can cause tongue discomfort and increased sensitivity to hot or spicy foods. But most people, besides seeing a change in their tongue's appearance, experience no other signs or symptoms.
Geographic tongue isn't triggered by an infection or another disease, and it's not related to mouth cancer. It doesn't have long-term health implications and occurs in otherwise healthy people. Though persistent and sometimes uncomfortable, geographic tongue resolves without treatment.
I don't think you can catch it.
Oral Thrush is an overgrowth of a yeast (fungus) called "candida." Candida is normally found on the skin, in the stomach, colon, vagina, rectum, mouth, and throat. Candida causes health problems only when there is an overgrowth in one of these areas of the body. The medical name for thrush is candidiasis.
These changes can occur as a side effect of taking antibiotics or drug treatment such as chemotherapy. These changes can also be caused by certain conditions such as diabetes, drug abuse, malnutrition, and as a consequence of immune deficiencies relating to old age or infection, such as AIDS.
Not sure if you can catch it but it doesn't sound like it.