Thanks for your query
Your son is having viral fever and it takes few days to settle.oral thrush is part of viral infection.
I advise you to continue with paracetamol
till fever is above 100F,do tepid sponging,give plenty of fluids,fruit juices,glucose water.
Apply nystatin over oral mucosa
,give some multivitamin
In case symptoms persist take him to pediatrician
to rule out any secondary infection.
Your child will be fine