Wudhu

Washing the face in wudhu

Q:

1. When the boundaries of the face are mentioned in the books of Fiqh, are the boundaries included in the washing i.e. is the bottom of the chin included and must be washed?

2. If someone came and said to you, "I can’t see the bottom part of my nose (just above the moustache) so must it be washed? What would you say to him when telling him about the definition of the face?

Repeating salaah if one found out that wudhu was not valid

Q: I was sitting after performing salaah when I noticed that there is a black, sticky substance on my foot through which water could not pass. It was the size of a whole round fingernail, and I had not seen it before.

Then, my brother told me that he saw it since 3 or 4 days on my foot. I had also led jamaat during these days. Will I have to repeat all the salaah that I had offered on these days? Will those who followed me in jamaat also have to repeat their salaah?