thanks for your query
These white balls are the debris or keratosis
in the tonsillar cripts, at the back of tongue there are multiple small tonsils called lingual tonsils
and that is normal thing.
For that you need to do antiseptic gargles repeatedly after each meals, 5-6 times a day
Try to give tonsillar massage
(just with tip of index finger you have to press gently from lower pole of tonsil to upper pole)
Take some anti inflammatory drugs like tab chymoral