Does LOreal semi permanent dye COMPLETLEY wash out?

I have a medium brown color. I haven't ever dyed my hair before. I want it to be temporary, as in no stains or anything. It will go back to my hair color completely. I want to dye it to a slightly darker shade of BROWN not black. Just a darker brown. I just want to make sure it will COMPLETELY wash out. I also have a few blonde streaks in my hair (completley natural). They are all underneath and cannot be seen unless i lift up my hair. Will they go back to blonde, or will the be stained brown? Thank you (: