What is the ruling on not removing skin peelings that are difficult to reach during ghusl, and is ghusl invalidated if water dries on some parts of the body before it is completed?

We fear you may be afflicted with waswasah (whispers/obsessive thoughts). If these are non-dead skin flakes, then it is not obligatory to remove them, and ghusl (ritual bath) is valid with them present. Washing over them is sufficient for what is beneath them. As for some limbs drying during ghusl, this does not harm, because muwalat (successive washing without interruption) is not a condition for the validity of ghusl according to the majority of scholars.