The vision may be delayed:
Jaafar ibn Muhammad was told: How late is the vision? He said, "The Prophet of Allah(pbuh) saw as if a dog was speckled in his blood, and he was shaman ibn al-Jushan, the murderer of Hussein, may God bless him, and he was the most righteous of Allaah," and according to tafsir al ahlam the revelation was interpreted after 50 years.
The difference between visions and dreams:
There is a confusion of people between visions and dreams, the vision of God and the dream from Satan. And the vision from Allah is preaching or warning. With regard to the dream, it is from the Shaytan that he throws it into the imagination of man, to grieve him and wear it in his religion and to stop him from doing good.