You seem to have developed a contact irritant reaction to the hair colour. If the treatment suggested is not helping you, either a more potent topical steroid
can be used along with better anti histaminic medication or a course of oral steroid can be added to alleviate the symptoms as early as possible. As the course of treatment depends on the skin lesions, a proper skin examination is required. Kindly consult your dermatologist
again so that amendments can be done. Take care.