Hello and welcome to HCM,
White patches on the tonsils can be due to accumulation of exudative material on the tonsils.
Exudative material over tonsils is due to infection.
Diphtheria is an infectious disease which is characterised by white colored membrane over the tonsils.
However, diphtheria is accompanied by
malaise and prostration.
As you have mentioned that a stone is identified in the tonsillar crypts.
Tonsillar crypts are clefts on the tonsillar surface.
Food debris and oral bacteria usually lodge in these srypts.
These crypts can become a site of formation of stones.
Thus, removal of the stones and antibiotics are mainstay of treatment.
I suggest you to consult a surgeon for clinical assessment and treatment.
Thanks and take care
Dr Shailja P Wahal