Why does the hair not look neat / look blurred?

There are several potential causes: lines too close one another; too much shading; the needle has been applied too many times; unstable needle, the needle was more suitable for shading; incorrect tilting of the needle which makes the colour grainy underneath the skin; the skin is oily; the colour has been injected too deeply underneath the papillary dermis due to excessive pressure and as a result it looks blurred.