What's up with bruising days or weeks after a sprain?

I sprained my foot on Thanksgiving, and today I noticed bruising at the base of my toes. It’s just recently started feeling worse, so I called my doctor and left a message asking if I should come in (she didn’t see me originally, I had to hit urgent care because it was the day after Thanksgiving.) So, seeking medical advice from an actual doctor, just have a question about how this works.

I was talking about it to other people who all said that yeah, sometimes when you sprain something, days or weeks later you get bruising way downstream from the injury. I’m guessing it’s blood pooling down, right? But why does it wait so long? Where was it before? Why couldn’t I see it then, but this morning I can? (Thinner skin at the base of my toes?)

Deep bleeds take a while to migrate to near the surface. Many never get to places where they’re visible. They follow paths of least resistance. If said least resistance is minimal or marginal, migration may be slow to non-existant.

Doesn’t the blood in question clot, though?

When an injury such as a sprain or a break tears blood vessels enough to cause bleeding, the blood does clot. However the material (including red cells) forming this clot is subsequently broken down and the hemoglobin itself is further broken down into substances of various colors.

The (broken down) hemoglobin in the tissues migrates, usually in the direction of gravity along fascial (connective tissue) planes and frequently pools near fascial attachments. A bruise in the leg, for instance, might eventually show up as a discoloration along the border of the medial and lateral heel area. etc

That’s really interesting! How does it eventually go away? Does the hemoglobin just decompose, or get absorbed by something, or what?

It gets consumed by white blood cells, and eventually gets shunted out the liver and into the bowel as bilirubin.