Have you ever had a 'bad batch'?

I get my roots touched up every 8 weeks or so. I love my stylist but last night when I was drying my hair I noticed a foil line. Like a spotty section where a horizontal line goes across unhighlighted hair! It's under a little bit, but close to the crown. If I part it the wrong way it would be really noticable.

Has this ever happened to you? What would you do??

It was so hard to schedule an appointment.... ugh..