Hi folks, any ideas on this ? I am using a Cintiq, and in normal painting “mode”, it carves into the texture, but I cant get nice bulges and soft features like in scultping mode 
I constantly have to smooth it out and I tried every stroke profile Maybe my node stup is wrong/incomplete ?
I’m not sure how much it’s affecting your efforts, but you appear to have multiple UV islands overlapping.
As @Magnavis mentioned: your UVs are overlapping → not good.
I set the Bump node’s distance value to (circa) the max height that the bumps should have. That helps me alot in generating exected normals.
Have you tried the little pencil buttons near the strength/radius values in paint mode? 
Try converting your image to a 32-bit float. Non-float (byte) images allow only 256 greyscale values which isn’t enough for a smooth gradient.