I coloured my hair for the first time this morning and inbetween dc pestering me I obviously haven't put enough on and it has not dyed in a couple of places.
If I get another bottle do I then put it on for the 30 minutes it says if undyed as parts are the natural colour or the ten minutes it says if you are topping up faded because the rest is already died? 
And wont the redying bit go even darker and the patchy bit still be lighter and mean it is still patchy ?