I appreciate that you want to learn more about Islam and in depth. You need not be apprehensive while you are on the path of learning with the commitment to surrender to what you understand as the commandment of Allah.
What I tried to clarify is that the Qur'an has, by virtue of an exemption, allowed the ladies to reveal their hands, feet and face.
It however has not taken up the issue of head covering. I mean it has neither asked the ladies to cover their heads nor allowed them to reveal them in the same manner as it exempted hands, feet and face. Their is neither order nor exemption regarding head covering. Any directive which is not mentioned in the Qur'an does not mean that the relevant act is perfectly allowed. For instance, the Holy Qur'an has not given any directive regarding gay marriages, distribution of inheritance of parents to their departed son's children etc. Obviously, about these matters we need to decide in the perspective of other similar directives of Islam, moral teachings of Islam and our innate guidance. While understanding the hijab directives, one should understand the following:
1. The addressees of these directives are not supposed to be savages. These are the people who are already living in a religious civilization - where many moral principles prevail and are acknowledged as such.
2. The edifice of Islam is standing on moral principles; it is the religion that values Haya (modesty); it is the religion that ordains that one should not go even near Zina (extra marital sex); it is the religion that aims at inner purification - to rid us and our surroundings of all immodest pracitices and thoughts.
3. The directives of social interaction are not the directives of the details of dress; these are the directives which pinpoint the areas of concern which all Muslims should consider.
In summary, while the Qur'an has exempted the hands, face and feet, it has not said anything about the head covering, which is still be decided by the Muslim ladies as they decide about many other matters where the Shari'ah is silent.