Hi Ford @Ford ,
I assume the top two images are the current situation.
There are several thing you can try; there is a Slide Relax Brush, and you can try the Smooth Brush, with the Deformation changed from Laplacian to Surface:

But the probably easiest way, is to go into Edit Mode and Select that area and its surrounding Vertices and then (right click or in the Vertex Menu) Smooth Vertices:

Then in the ‘Adjust Last Operation’ Panel, you can increase the iterations until you are happy with the result.
Maybe you need to use a combination of these techniques.