Has anyone used this before? I had it done over a year ago and it seems to be going back to its former color. i though the results were supposed to last for years. Do they do touch ups or do I need to go for the whole thing again?

Has anyone used this before? I had it done over a year ago and it seems to be going back to its former color. i though the results were supposed to last for years. Do they do touch ups or do I need to go for the whole thing again?
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