I tried an at home medium dark brown hair die. It is just a
Little too dark for me. What can I use at home to lighten it
Just a little bit?

Your too-dark hair dye is permanent, it can sometimes be faded by washing with a clarifying shampoo. Use one that is designed to remove product build-up or chlorine build-up from swimmer's hair..

Artificial hair color will fade and get a little lighter each time you shampoo your hair. If you want to fade your hair color a little bit, you can also use Prell, dandruff shampoos or dish detergent to help accelerate the fading process. These methods can make your hair feel dry, so be sure to use a moisturizing conditioner afterwards to restore moisture onto your hair. Another option is to use a 20-volume peroxide developer with your selected hair color to lift the color a couple shades lighter.