Question
During Hajj, when I came to casting the pebbles, I doubted the number of pebbles which I had cast in the pit. So, I considered the lesser number in order to be sure that they were seven. When I cast the pebbles of the next Jamrah and counted the total number of pebbles, I discovered that eight pebbles were thrown at the first Jamrah, because I had a certain number of pebbles with me. Am I required to do anything?
Answer
All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His Slave and Messenger.
Since you considered the lesser number when you doubted the number of pebbles you cast at the Jamrah, you have indeed done what you were required to do. If you later discovered that you had casted eight pebbles, this is not harmful because you have fulfilled what you are required to do.
Allah Knows best.