I have salon blond highlights in my light brown hair. Can I use a store product to make it lighter all over?

Yes, you can, but be careful. I had highlighted my hair for a long time, and then I wanted it all one color. I went to Walmart and got a kit. I didn't do the test, and I had a massive allergic reaction. You can dye it but just make sure you do the test to make sure you won't have a reaction. I had to go to urgent care, get a shot of steroids, and was on steroids to two weeks!