Is it permissible to comb and blow-dry hair after performing ghusl with the intention of ihram for Hajj?

It is permissible to dry hair before or after assuming ihram, as long as it is not done with a perfumed substance. Combing the hair (تسريح الشعر) after assuming ihram is disliked because it may lead to hair falling out. If live hair falls out, a fidyah (expiation) is due. If dead hair falls out, there is no obligation. It is recommended to offer the fidyah in case of doubt, as a precaution.