What must I do after remembering during Sa'y that I had not removed the transparent nail polish, knowing that I completed the Sa'y and have not yet exited the state of ihram?

If the nail polish prevents water from reaching the skin, then ghusl (ritual bath) and tawaf (circumambulation) are invalid according to the majority of scholars. The nail polish must be removed, and only the affected area needs to be washed, without the need to repeat the entire ghusl. It is obligatory to repeat the prayers that were performed in this state, and to repeat the tawaf and sa'i (ritual walk). However, if the nail polish does not prevent water from reaching the skin, then the 'Umrah is valid.