White marks on tattoo after a month and a half

So I got a tattoo almost 2 months ago and these white marks have been occurring since 2 weeks in. I have 2 sessions with this artist my next is in a couple days. The artist told me he still has work to do on it and he is going to shade in the white marks. And says it is no big deal. Most people say yes he will shade it right in and a couple others say don't go back to this guy. This is my first big tattoo so I am very nervous about the outcome. Does anyone have an opinion on it ?