I recently had my blonde highlights dyed over and had a colour a lot darker than my natural colour put on but I hate it its too dark. What can I do to lighten it? Will getting it stripped ruin my hair?

Go back to the salon where you had your hair coloured and explain that you are not happy. A bleach bath can sometimes be used to lift colour but this must be done by a professional in salon or you could damage your hair. The salon you originally went to should be pleased to help you and resolve the matter.