The camera ra filter is not the same as the camera raw processor, and it's not the same file anymore.
When the file is processed in ACR and opened into Photoshop, all those adjustments are baked into the pixel data. It is no longer the raw file you started with, but a rendered RGB file. You're starting at zero again, it's a new file.
It is possible to go back, but with a different workflow to begin with. Then you need to open the file from ACR as a smart object. A smart object embeds a copy of the original raw file inside the PSD/TIFF master file. This can be reopened, with the original settings, re-edited in ACR, and then resaved back to the master file.