Welcome to HCM.
Based on the information provided the cause for the burning tongue is most likely to be due to Vitamin deficiency
Neither Fructose intolerance
nor PCOS cause such symptoms.
You have never mentioned whether you had any ulcers on tongue.
Deficinecy of Riboflavin, Zinc and Vitamin B12 often presents with similar complaints. So, taking multivitamin
capsules containing these vitamins and minerals
will relieve your problem.
Hop you got the solution you were looking for.
Wish you a speedy recovery.