Scalp micropigmentation (SMP) side effect - can it cause brain cancer?

After a week from your microneedling, you can have Scalp Micropigmentation as the microneedling should be healed. If you are concerned give it an extra week

If the SMP is performed with a light gray with some brown color in it, then you should keep up the hair dying process and the SMP might work provided that the gray roots did not show very much.

It is possible that SMP could help make the overharvested region look less noticeable. But it really depends on a number of factors. Pigment is really a 2D solution. In other words, pigment applied to an empty skin area will be quite obvious if the surrounding areas are marked by real hair...