Prophet (SAW)'s Prayers

For any calamity
When any calamity comes, even if pricked by a thorn recite:
إِنَّا لِلَّهِ وَإِنَّا إِلَيْهِ رَاجِعُونَ اللَّهُمَّ أَجِرْنِي فِي مُصِيبَتِي وَاخْلُفْ لِي خَيْرَاً مِنْهَا
"Definitely we are from Allah and to Him is our return. O Allah, grant reward in my calamity and grant in its place a good substitute".

If there is an infection on the body, wet the Shahaadat finger with saliva from the mouth, place it on the ground and then rub it on the infection while reciting:
بِسْمِ اللَّهِ تُرْبَةُ أَرْضِنَا بَرِيقَةُ بَعْضِنَا لِيَشْفِيَ سَقَمَنَا بِإِذْنِ رَبِّنَا
"In the name of Allah, with the blessings of this soil of our land which I mixed with the saliva so that the ailment is cured by the order of our Lord".

(Bukhari, Muslim)
If there is pain on the body, place the right hand on the pain, recite "Bismillah" thrice and the following dua seven times:
أَعُوذُ بِاللَّهِ وَقُدْرَتِهِ مِنْ شَرِّ مَا أَجِدْ وَأُحَاذِرْ
"I seek refuge in the Being and Power of Allah from the effects of which I am in and from that which I fear".

(Hisnul Hasin from Muslim)