Here is a very effective dua to remove fever. This dua is recited by Saad Al-Qureshi. May Allah protect and cure us from illness.

بِسْمِ اللّٰهِ الْكَبِيرِ أَعُوذُ بِاللّٰهِ الْعَظِيمِ مِنْ شَرِّ كُلِّ عَرَقٍ نَعَّارٍوَمِنْ شَرِّ حَرِّ النَّارِ

I seek relief taking Allah’s great blessed name from all the evils of pulling (pulsating) nerves and from the evils of the hot fire”.

This is reported in At-Tirmidhi.