Hi..
Welcome to HEALTHCARE MAGIC..
As per your query and presentation of symptoms the white spot over the tongue which comes and goes seems to be Recurring Apthous Ulcers while other cause of a recurring spot on the side of tongue is a
mucous cyst known as Mucocele..
Apthous ulcer can be due to a number of reasons like
Nutritional deficiency of Iron
Vitamin B12, folate, stress, physical injury with sharp tooth, tongue bite , stress etc..
While Mucocele occurs due to injury t minor salivary glands or its ducts leading to spillage of mucous into
soft tissue..
As it is not persistent and keeps on coming and going it does not seems to be anything serious..
You should definitely consult an oral surgeon or an oral physician and get evaluated and on case of Mucocele concentrated salt water rinses can help..
If it does not resolve surgical removal is to be done..
If it is a
canker sore taking multivitamins and warm saline gargles will relieve..
Hope this information helps..
Thanks and regards..
Dr.Honey Nandwani Arora.