Seeing mustache in a dream could have different meanings in Islam depending upon the context and the situation.
1- Mustache in a dream represents the power, dignity, or stature of the man.
2- Getting a mustache trimmed with scissors in a dream has a good and positive meaning.
3- Seeing a dream where a mustache has fallen from the body means that it would negatively impact the power, dignity, or stature of the man.
4- According to Ibrahim Karmani رحمة الله عليه seeing a dream where the size of mustache has increased means strength and power.
5- A dream where someone shaves off the mustache of the dreamer means a fight.
6- Long mustache in a dream means sadness and sorrows.
7- On the other hand, a small mustache in a dream show respect attainment, and fulfillment of desires.