Just dyed my hair hair jet black skin is to pale and I look like death is there anything I can use to cover it natraural medium brown

Since you used a jet black permanent hair color, you will need to use a hair lightening product to make your hair lighter. Your best bet is to pre-lighten your hair to a level that is lighter than the color you want and then apply the desired color. However, you can use your selected hair color with a 30-volume peroxide developer in equal parts to achieve results, but it could produce unpleasant shades. If possible, get your hair professionally done.