Doubts (wasawis) in whudu

I am suffering from waswasah, less severe than a while ago though, AlHamdulillaah.

Please answer my questions, so as to educate myself and to vanquish the stray thoughts.

1)

When wiping the head, what is our aim?

Is it to make sure each hair has been wiped with water? Or is it just to wipe the area?

2) 

Is a little amount that is still left on the skin after wudoo’ excused? Like, I do wudoo’ and I think I have slight eczema on my palm and I still see when my hand dries, little tiny bits of skin, about the size of the hole of a needle, and even if I rub my hands, this still happens. So is a small amount excused?

In the Name of Allah, the Most Gracious, the Most Merciful.

As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.

1. When making masah of the head, wiping a quarter of the head is sufficient. It is not necessary to wipe every strand of hair[1][2].
2. As a general rule, the whudu made on the skin attached to the body at the time of performing whudu is valid. The dry skin coming thereafter does not invalidate the whudu[3][4].   

Furthermore, if you are to have negative thoughts after performing whudu correctly and thoroughly, reciteلاحول ولاقوة الا بالله  Thereafter, do not entertain such thoughts. They are baseless and from shaytaan. Consulate a physician to examine you for eczema.

And Allah Ta’āla Knows Best

Abdullah Ghadai

Student Darul Iftaa
Michigan, U.S.A 

Checked and Approved by,
Mufti Ebrahim Desai.