There are many reasons why there are so many small red dots under the tongue, and the common ones are lingual inflammation, papillitis of the tongue, scarlet fever and so on. 1. Tongue inflammation: it is an inflammation that occurs in the tongue, and usually there are symptoms such as swelling of the tongue and color change, etc. Many red dots can appear under the tongue. 2. Papillitis: Inflammation of the papilla of the tongue caused by a variety of reasons, many small red dots can also appear under the tongue, often accompanied by symptoms such as congestion and edema of the tongue. 3. Scarlet fever: it is an acute respiratory infectious disease caused by hemolytic streptococcus, which is mainly manifested by fever, sore throat and diffuse red papules all over the body. The rash may be accompanied by swelling of the papillae of the tongue, red dots on the tongue, often accompanied by loss of appetite, nausea and other symptoms. There may be other reasons for the many small red dots under the tongue, and you should go to the hospital in time to find out the cause and standardize the treatment.