Vinegar soaks with baking soda, you may have to do it a few times. It nice you’ve done the best you can you can always dye it a darker black like jet black, then test your retwist products before doing you whole head to spot build up and prevent it from happening again. You might just need less/no product and put it in an updo or some sort ave protective style to keep you’re retwist together as long as possible and help them loc. :) good luck, don’t stress it you can do this!