can highlighted hair be touched up at the roots?

[cheeryface]

i have dark blonde hair with lighter blonde highlights. when the roots start to look dark could i have them touched up without going over the already dyed hair?

Yes, I had this done just the other day.

I don't usually highlight my hair but two lousy summers and no holidays abroad made me feel a little dull.

I had highlights a shade or so lighter than my natural colour done last Nov so had about 1-2 inches of roots. Hairdresser did foils as before but just painted on the colour to those couple of inches.

Wasn't any cheaper than the first lot of full highlights though.