What is the ruling on a pilgrim in a state of ihram covering his head if he is bald and his skin is very sensitive to the sun's rays, given that he cannot carry an umbrella?

If you cover your head while in the state of Ihram, you are liable for a Fidyah (expiation): slaughtering a sheep to be distributed among the poor of Mecca, or feeding six needy people in the Haram (each person receiving half a sa' of dates or the staple food of the land), or fasting for three days. This applies to Ihram for both Hajj and Umrah.