I heard the Prophet ﷺ saying, "A good dream is from Allah, and a bad dream is from Satan. So if anyone of you sees (in a dream) something he dislikes, when he gets up he should blow thrice (on his left side) and seek refuge with Allah from its evil for then it will not harm him."
سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ الرُّؤْيَا مِنَ اللَّهِ وَالْحُلْمُ مِنَ الشَّيْطَانِ فَإِذَا رَأَى أَحَدُكُمْ شَيْئًا يَكْرَهُهُ فَلْيَنْفِثْ حِينَ يَسْتَيْقِظُ ثَلاَثَ مَرَّاتٍ وَيَتَعَوَّذْ مِنْ شَرِّهَا فَإِنَّهَا لاَ تَضُرُّهُ وَقَالَ أَبُو سَلَمَةَ وَإِنْ كُنْتُ لأَرَى الرُّؤْيَا أَثْقَلَ عَلَىَّ مِنَ الْجَبَلِ فَمَا هُوَ إِلاَّ أَنْ سَمِعْتُ هَذَا الْحَدِيثَ فَمَا أُبَالِيهَا