The beginning of the file is filled with the word ‘page’ repeated, and also a lot of zeros. There isn’t anything in the file to suggest that it’s a SketchUp file. At the very least, something in your damaged the first part of the file.
You should look in the same folder for a file with the same name, but that ends with .skb instead of .skp. That would be the backup file, and hopefully it’s ok. Rename that file and change the extension to .skp, then see if it opens ok.