If you really lucky they didn´t use fabric dye and you can bleach the knots. If the did, you wont be able to bleach anything or at least end up with a orange looking scalp. Regarding coloring the unit i suggest this as your best option, but it can be very tricky. I would stay miles away from Back2Natural as it goes very dark in your system. This color depositer only consist of different degres of BLACK and is completely useless for systems with red/brown in them, unless they got a good portion of black too, in opposite to your system. I suggest color unit, color your own hair. You´ll need to take color sample and check the time for both your hair and the unit before making sure you get a match. It is quite the headache. And I suggest you wear the unit with bangs as I do not believe you´ll be able to bleach the knots well enough when the front is colored.

Best