You should be able to return to your usual blonde tones no problem. If you can wait till your next appointment then I would ask whether you can have the colour you had before the darker set of highlights.
This shouldn't be too difficult as all they are doing is re-highlighting the old colour. If you are really unhappy with it and want it doing straightaway then just speak to your colourist and see if they can just lift out the deeper tones and it should be quite simple. I would try and wait however until you are due for your next colour as over time this colour will fade and it will be easier to change.
Remember to keep your hair healthy and use moisture and protein treatments to keep your hair looking its best.
