Hi
welcome to HealthCareMagic
If fever is persisting for last 6 days , it need proper evaluation including investigations to find cause of fever .You have not mentioned associated symptoms and general condition of baby .
Common causes are viral including dengue,
malaria,
typhoid, urinary infections, infections of
respiratory tract or GIT.
You can always do tepid sponging to bring it down if not coming down with antipyretics.
Watch for any danger signs like dullness, poor oral acceptance ,
vomiting, pain abdomen, cold extremities, decreased urine , headache which is indication of urgent consultation
Take care
revert back if any other query
thanks