Select your edge loop than convert it to vertices with Edit Polygon>>Selection>>Convert selection to vertices. Then you can use the Polygons>>Average Vertices tool which has a similar effect as relax UV. Or with the vertices selected you can use the Edit Polygons>>Sculpt geometry tool set to Smooth.
I'm not sure If this is what you're looking for, but often If I have a surface that is a little on the bumpy side for my liking, I'll grab the verts in that area and hit polygons>average vertices. In concept it's very similiar to relaxing.