nvq2 care:z7 the signs in racial skin of pressure sores?

This is an interesting question and I don't recall having seen the problem in question ever addressed before.

In the white person, usually elderly, but not always, the affected skin would start to turn pinkish, before it "broke down" to form the ulcer.

In the black person, the pink color might be harder to pick up, but I would suspect , that the color of the affected skin layer would change, as would the texture of the skin, prior to it's "breaking down".
If you push on the skin with your fingers, the affected skin section may, feel "mushy", because of it's deterioration. One might suspect that melanin production would also be affected, and thus the normal darkish color would also be affected.