Will Hair Regrow the Same Color After a Scalp Dye?

You can't dye your scalp. Scalp dye is not a thing.

Hair dye is designed to color the hair shaft, not the skin. If you shave your head, you are removing the hair shaft. Any dye applied to your scalp will only color the skin temporarily and will not affect the hair that grows back. The hair will grow back in your natural color.