But wouldn't having food type material imbedded into the wound foster infection?
We're talking purified starch -- carbohydrates -- and some protein, not a ham sandwich.
Essentially what you're doing is making your own ersatz gelfoam (gelatin based).
I would not want to, however, spread the cut wide and force the material deeply into the wound, and that's not what I was suggesting.
Pressing your finger straight down into the flour will cause a little of it to be packed into the upper surface layer of the wound, but the blood will gelatinize that layer very quickly, essentially forming a seal that will help hold blood and and keep more of the flour from being forced into the wound.
In essence, if it's bleeding heavily enough, you make your own compaction dressing.