If the child has been started on meds & 4 days passed , you can restart milk while maintaining oral hygiene.
As such there is no contraindications.
I am assuming the baby is mainly on solid diets and milk is just given once /twice in a day .
Next Steps
Continue feeds as usual . Keep the mouth clean .
Do not try to wipe away the white patches forcefully .
Health Tips
Watch for any increase , fever , or any other . Consult immediately. If occurs repeatedly,will have to investigate .