Want to try henna in my hair but i have a serious question help!!!!!!!!!!!!!!!!!!!!!!!!!!…

i have dark brown hair its not my real color ive dyed my hair so much over the last year i had to cut it to my collar bone and then the hair stylist wouldnt touch my hair because of the damamge..its not terrible but dry enough lightening cause breakage..im a natural red head and i want to go back to red hair..if i appy henna to my dark brown hair what color will i get and what condition will it leave my already damaged hair in?