What is the sole of your foot made of?

That looks horrible! And I think it’s just tissues and such, but it may be harder since you walk around and put pressure on it all the time. I hope that it gets better soon!

Calloused skin, if you walk around barefoot a lot.

Sorry, that was smart ass answer, what did you do? The blood isn’t exactly “draining”, that line is, it’s just where the bruising ends. I’ve never seen a bruised sole of the foot but you don’t generally see the soles of people’s feet. Anyway, I really don’t know. Looks bad though.

First of all, there is a thick band of tissue that covers the bottoms of the bones across the sole of your foot called the plantar fascia. Under the skin, of course.
Secondly, it isn’t uncommon for blood to pool around the ankle just the way that it has on yours. It is possible that there is bruising further down into your foot and heel beneath the skin, but that it isn’t as visible through the thicker, calloused skin on the sole of your foot.
That’s a nasty injury, by the way, I hope you’ve seen a doctor?

Correct. Blood isn’t ‘draining’... this is bruising and it shows through on the skin that is less thick. The skin on the bottom of your foot is thicker. You’ll notice that this is the skin that ‘prunes’ when you take a bath. It’s a thicker layer of epidermis made up of dead skin and keratin. The cells on the bottom of our feet become protective, specialised, stratified epithelium cells so that the outermost layers can endure abrasion without blood loss, so they have thicker layers of dead skin to protect the blood vessels. There is probably more bruising under that area, but you just can’t see it.