Ive had an allergic reaction to hairdye, can i dye my hair again if i dont have contact with my scalp?

ive had 2 reactions (contact dermatitis. generally feeling unwell, tight forehead and itchy ears and nausea. no swelling or lumps etc) to hair dye using light brown and was wondering if it is safe to use again if i don't do my roots and have no contact with my scalp? i dyed my hair in between these 2 reactions (a dark brown) and was absolutely fine. or should i use a semi permanent or naturtint or could i take a antihistamine prior to dyeing to prevent any allergies! i know some will say do not dye my hair again but i need to do it one last time to match my roots and then i can let it grow. please help me! thanks in advance.x