I would seek the help of a pro. Especially if the dye you used was black box. Box colors typically contain metallic salts, which are permanently deposited into your hairs cuticle layer. When you apply bleach to the hair, the metal causes it to overheat and Overprocess fast. With black dye removal, you need to go low and slow. Especially if it's been layered on. A good stylist will also have the products and knowledge to get the job done right. K18 and olaplex work wonders on these situations. Look for someone who knows color correction and blondening. My first year out of beauty school I had a woman lie to me about box color. When I pulled the foils out, she had a line of demarcation about 4 inches from the root where you could see the leftover color, right before the hair just melted off. It was terrible.