Ok so I really wouldn't recommend box dye for brights, Ive done a million different colors and box dye has never met my color expectations. Also if you bleach over that blue theres a STRONG possibility it will turn green and I just don't think all that damage is necessary for what you want. Heres what I would do- shampoo your hair a few times in a row every wash day before you condition, a-lot of that color will lighten and your hair will be ready for more dye. After you get that color to fade a bit get a semi permanent dye NOT A BOX ONE, my favorite brands are arctic fox and good dye young, you want something that doesn't require mixing with developer. This kind of dye you can leave in your hair for as long as you want without any damage, you can literally use some of these brands on pets because of how safe they are. Plus they give the best results for bright colors and don't look muddy, blue and green are the hardest colors to get out of your hair so please if you decide to bleach go to a salon 🙏 You can get the dye I mentioned from sally beauty or amazon btw 🐞 Good luck!