How do I expand a mask equally on all sides?

[241430371jn3]

I have a silhouette of a human on transparent background that has an auto traced mask and when scaling it up it doesn't fit properly for what I'm trying to do. The neck part of the mask ends up squeezing into the head as I expand it, and the mask doesnt surround the silhouette properly at all even if I reposition it. The only way I found of doing it is manually drawing the mask, but I need absolute precision so it doesn't work.

What I want is for the space between the mask and silhouette on the left and right of the neck to be the same as the torso and head. Like if you were adding a layer of fat to the entire body equally, the neck width would scale the same amount as the torso, not less, as in regular scaling.

[J_Nas · Accepted solution]

So just to be sure I understand it correctly, for scaling up the mask you now use Mask Expansion and that is not giving the result you are after? Because that's how adding a 'equally layer of fat' would look like. 

[241430371jn3]

I didn't know about Mask Expansion but that was exactly the type of scale up I was looking for. It didn't expand the mask itself, but I found a workaround by copying the mask to a solid, then using Mask Expansion, set mask to subtract then traced the cutout and copied the new mask back to my original layer. I feel like there should be a faster way though. Thank you for the help.