أَسْأَلُ اللَّهَ الْعَظِيمَ رَبَّ الْعَرْشِ الْعَظِيمِ أَنْ يَشْفِيَكَ
As’alullaahal-‘Adheema Rabbal-‘Arshil-‘Adheemi ‘an yashfiyaka.
I ask Allah who is the Lofty and the Lord of the Mighty Throne that He cures you\n(Prophet Mohammad (SAW.) said that by reciting this dua seven times, the ill person will regain his health and if death occurs then that (death) is a different issue (i.e. death is written it cannot be prevented))
At-Tirmidhi 2:210