I did my hightlights myself. I only do the top. The underneath is my natural color. When I did it . It didn't come up all white . Some highlights had a yellow tone. So I went and got a toner with 20% and left it on for about 15 minutes. I think the color was called toe head. But the color is so dull> I want the white or very light blonde back. Is there anything I can put on it to brighten it again. Keep in mind my hair is very dry on top so I am trying to stay away from strong peroxide

20%? Or did you mean 20vol? Either way this was not a true toner you put on your hair, it was another colour, as toners don't contain % or vol, they are designed to leave small deposits of colour within the hair shaft and NOT lift hair colour.
The reason the highlights went yellow was due to the fact they were underprocessed, or your natural colour was to dark for the strength of product you applied. (you have mid/dark brown hair I'm guessing)
As your hair seems to be very damaged and dry due to the chemical processes its undergone I would advise against any more colouring and concentrate on getting your hair back into good condition. Then treat yourself to a T-section of foils at the hairdressers, they will be able to gauge the correct colour and strength for your hair.