If I have highlights, can I use a wash-out "light brown" hair color that washes out in 21-

If I use a semi-permanent hair dye, will it completely wash out, or will it leave any remaining color after the listed '28' washes?

I'm trying to buy a couple months or so before I have to get my highlights done, but I don't want to have to re-do the whole thing, or ruin my highlights.

If I have highlights, can I use a wash-out "light brown" hair color that washes out in 21-28 washes or so?

semi perminent color will cover your highlights. it will hold for ever. may lighten but it will ruin your highlights. if you use a blonder color it will tone your highlights. but be aware your not a professional. tred lightly. do a patch test first underneath. so what happens. hope it helps.