What PS changes have been made to the picture? I want to take part in a photo contest, only asking for color change, not addition.

Generally speaking, you need to provide pictures in RAW format for the photo contest. I use Capture NX 2 to process RAW (Nikon NEF format) photos. When this format picture is opened, it will show your processing process from the original photo to the final product.

I haven't tried whether the photos processed by PS plus RAW filter are recorded in this way, but if they are in RAW format, there should be this record.

It is acceptable for a photo contest to adjust the brightness contrast, dust removal, rotation and cropping of ordinary photos; But you can't add composition or delete content, then RAW photos can be seen and will not be accepted.