What is the ruling on the ablution (wudu'), ritual bath (ghusl), and prayer of one whose body has been adhered to by an unperceivable paint for two days, and how did the Prophet (peace be upon him) wipe his head?

If the aforementioned paint is light and does not prevent water from reaching the skin, then it is not necessary to remove it for wudu (ablution) or ghusl (ritual bath), and the prayer is valid. However, if it is thick and prevents water from reaching the skin, then it must be removed, and the affected area must be rewashed along with whatever was prayed with, but it is not necessary to repeat the entire ghusl.

Sheikh al-Islam Ibn Taymiyyah held the view of excusing a minor barrier that prevents water from reaching the skin, but the preponderant opinion is that of the majority of scholars, which necessitates its removal.

Most scholars agree that the Prophet, peace and blessings be upon him, used to wipe his head from its front to its nape, and the well-known and common practice, which the majority adheres to, is to begin from the front of the head to its back.