Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain you have white stuff at the back of the tongue along with a dark dot and red rashes.. The white stuff can be most probably be due to yeast infection of the tongue also known as Oral Thrush while white dot can be inflamed circumvallate papillae and red rashes can be due to inflammation secondary to infection.. I would suggest you to consult an Oral Physician and get evaluated and a thorough clinical evaluation and investigations like microscopic examination of scrapings from the white layer can help in diagnosis and treatment can be planned accordingly.. If thrush is confirmed as the cause you can be advised to take anti fungal mouthwash like Nystatin mouthwash.. You can be advised to such antifungal lozenges like Clotrimazole.. You can be advised to take plenty of probiotics like Yoghurt and garlic.. Drink plenty of water.. Do warm saline gargles to reduce the inflammation.. Maintain a good oral hygiene.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.