Yes, you can cover bleach stains with dye. In order to ensure that your garment is the same color all over, it might be best to first bleach the whole garment with a fabric color remover (such as Rit Color Remover), then dye the entire garment according to the directions on your preferred dye. You can also try coloring in the stain with a fabric marker that matches the color of the rest of the clothing.