How can I make blonde highlights look less grey?

I've had blonde foils put in my natural brown hair but the blonde now looks very grey. Is their a way to tone it to a darker blonde? Please help, I'm too young to be grey!How can I make blonde highlights look less grey?
Don't use violet shampoo. Violet shampoo is meant to brighten blonde hair and what they mean is that the blonde highlights would look more white. I used it all the time when I had highlights, and they were super bright white. If you use too much violet shampoo, then your hair gets a very obvious grey or purple tint. I would recommend getting a warm toner rinse because or not getting ash highlights next time. I find that brown hair when mixed with blonde, especially if the brown is darker, does made it look grey for some reason.How can I make blonde highlights look less grey?
there is this ultraviolet shampoo you can buy at salons. It is very brights purple and makes the blonde shine thru. good luck :]
Use a more yellow color rather than an ash. Ash based color can make people appear to have grayish hair.