To dream of a person or creature with horns represents your awareness of others negative or evil intentions. It may also reflect some aspect of yourself that is behaving this way. Unwanted sexual aggression.
To dream of yourself having horns on your head represents your awareness of yourself being totally consumed by yourself. Doing whatever it takes to get what your way. It may also reflect awareness of your total absence of morals to achieve your goals. You are “pure evil” in winning. Preferring or enjoying total negativity. Awareness of your own negative intentions. Enjoying getting away with being arrogantly powerful over others. Evilly outsmarting others.
Alternatively, dreaming of yourself having may reflect awareness of your own sexual aggression.