Simplify the following text for a Grade 8 native English-speaking person.
Original: The outside of the foreskin is a continuation of the skin on the shaft of the penis , but the inner foreskin is a mucous membrane like the inside of the eyelid or the mouth .
Simplified: The outside of the foreskin is like normal skin but the inside of the foreskin is a membrane like the inside of an eyelid or mouth .