Answer in Details
Sometimes, Lord Shiva is worshipped in the form of Ardhanarishvara—a composite of Shiva and Parvati (Shakti), symbolizing the unity of masculine and feminine energies. This form shows that Shiva and Shakti are not separate but exist together in every living being.
If you are referring to spiritual experiences or visions where Lord Shiva appears on the body or through the form of a girl, it is seen as a divine blessing and a reminder that the Supreme Consciousness is present in all. In bhakti (devotion), many devotees have experienced Lord Shiva in different forms, as per their faith and devotion.
Ultimately, Shiva’s teachings emphasize seeing the divine in all beings, transcending external appearances, and realizing the oneness of all creation.
Om Namah Shivaya.