Question:1)If a junub performs Ghusl but forget to wash the nostrils, then after ghusl he remembers this, then does he have to perform ghusl from beginning again? 2)Also what about wuzu? if you forget to wash face and remember couple of hours later?
1. If he remembers after the Major Ablution (Ghusl) he can wash the nostrils and Ghusl will be fine
2. Same as above. Though to wash each part one after the other in Sunnah (and Wajib in some schools of thought). Therefore Wudu will be valid but there sahll be reduction in the Thawab (reward).
The above two will only be valid if someone does not break his Wudu. If he does, then of course, he will re-do his Wudu.