Whoever recites this:
أَعُوذُ بِكَلِمَاتِ اللَّهِ التَّامَّاتِ مِنْ شَرِّ مَا خَلَقَ
I take refuge in Allaah's perfect words from the evil He has created.
'A'oothu bikalimaatil-laahit-taammaati min sharri maa khalaqa.
…three times in the evening will be protected from insect stings.
Ahmad 2/ 290, An-Nasa'i, At-Tirmizi 3/187, Ibn As-Sunni (Hadith no. 68), Ibn Majah 2/266.