Prophet (SAW)'s Prayers

When fever or pain increases
If fever rise or pain increases:
بِسْمِ اللَّهِ الْكَبِيرِ أَعُوذُ بِاللَّهِ الْعَظِيمِ مِنْ شَرِّ كُلِّ عَرَقٍ نَعَّارٍ وَمِنْ 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".

It is prohibited to speak ill of fever. When Umme Sahabia (R.A.) spoke ill of fever then Prophet Mohammad (SAW) said, "do not abuse fever for it removes the sins of man like the furnace removes the rust from the iron".