However, he will be obliged to give fidya, even if he shaved his head due to some illness or pain in the head.

Sayyiduna Ka'b bin 'Ujrah (may Allah be pleased with him) narrates that during the time of Hudaybiyyah, the Messenger of Allah (peace and blessings be upon him) came to me while my hair was quite long and thick. He (peace be upon him) said: "It seems that the lice of your head are troubling you?" I replied, "Yes." He (peace be upon him) said: "Shave your head and sacrifice a goat, or fast for three days, or give three sa' of grain in charity to six needy people."