Healing is a sequence rather than a single look, which is more useful than one picture.
First days. The blood clots and dries to form a scab, which protects the tissue underneath from germs. Then your immune system begins protecting the wound: it becomes slightly swollen, red or pink, and tender, and some clear fluid oozes from it, which helps clean the area. That stage takes about 2 to 5 days.
Next few weeks. The body repairs broken blood vessels and new tissue grows over the next 3 weeks or so. The wound starts to fill in with new tissue, called granulation tissue. New skin begins to form over this tissue. As the wound heals, the edges pull inward and the wound gets smaller.
Afterwards. The area may itch. After the scab falls off it may look stretched, red, and shiny. A scar forms that is smaller than the original wound. It will be less strong and less flexible than the surrounding skin. It may fade and can take as long as 2 years to do so.
For an open wound, color is the clearest single marker. After cleaning or debridement, the area will be red or pink and look like fresh meat. Wounds that are pale, purple, or black are less likely to heal.
Two measures go with that, and they are both about direction rather than appearance. The wound getting smaller, which is part of the healing sequence. And for a packed wound, needing less packing: as the wound heals, you should not need as much gauze or packing gauze.
Against all that, the one thing that is not a measure of progress: how a wound looks at a single moment. A wound that looked worse after debridement may be doing better than one that looks tidy under a covering nobody can see through.
And here’s when the sequence is not happening. A wound is called non-healing if it has not started to heal in 2 weeks, or has not completely healed in 6 weeks.