Displacement maps filter

High, I´m painting some displacement maps, and when I subdivide the mesh to about 2 million polygons, I start to get some faceted effect, no matter if the image is in 32 bits or 8 bits or if I blur it.

So, I wanted to know if Blender had some kind of bluring filter that that could be apply to the texture channel. I´ve tried the Filter button, but nothing seems to change.

My image is 2048x2048, perhaps if I increase the resolution and I apply a 32 bits blur the problem will go away, but it would be much simpler and less RAM consuming if Blender had some kind of filter for displacement maps.

Ok ok. I got it. I didn´t have Cinepaint properly configured, and had some troubles with color profiles. Now that I set that up I can edit 32 bits native files and save them as EXR, and that solved the problem. With the 32 bit Blur all the artifacts disappeared.