There are many reasons why a white blister grows underneath the tonsils, such as tonsil stones, purulent infection of the tonsils, viral infections and so on. 1. Tonsil stones: tonsil stones are mainly due to the stimulation of chronic inflammation of the tonsils, tonsils have a large number of bacterial proliferation, the patient after eating food debris in the tonsils by a large number of bacterial wrapping, thus forming clumps, that is, tonsil stones, and make people think that it is a white blister. 2. Tonsil purulent infection: tonsil purulent infection will cause tonsil congestion, edema, which looks similar to white blisters, but also accompanied by high fever, chills, swallowing pain and other symptoms. 3. Viral infections: viral infections of the tonsil tissue may lead to a white blister under the tonsils, and later the blisters will break down and form an ulcer. There are many reasons why a white blister grows under the tonsil, after the symptoms, it is recommended that the patient must consult a doctor in a timely manner, to identify the cause of the disease, and follow the doctor’s instructions to take standardized treatment.