Answer
Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Kohl does not break the fast of men or women according to the more correct of the two scholarly opinions, but it is better to use it at night if one is fasting.
Answering your question, the late Saudi scholar, Sheikh Ibn Baz (may Allah have mercy on him) stated:
Kohl does not break the fast of men or women according to the more correct of the two scholarly opinions, but it is better to use it at night if one is fasting.
The same applies to soaps, creams etc that are used to beautify the face and are applied to the surface of the skin, including henna, makeup and the like.
There is nothing wrong with using them for one who is fasting, but makeup should not be used if it will cause harm to the face. (Majmu` al-Fatawa, 15:260)
Almighty Allah knows best.
Source: www.islamqa.info.