Some woods I’d hike/jog through had giant (100+ feet tall) mountains of dirt sitting around in an open area - for construction work, I think, but I’m not sure.
I used to run up and down those giant mounds for excercise… one day I was running down a rather steeply sloped (maybe 40 degrees) mound very quickly - it had rained earlier but most of the area was dry… but I managed to have my foot instantly sink into a mud pit while running down this hill.
So, my 250 pound frame (at the time) was going full speed down a steep incline (decline?), my foot instantly sunk into the dirt, giving me no chance to stop whatsoever… my body kept falling forward but my foot was planted in the ground… and the force exerted on my ankle was quite severe. The area wasn’t really accessible by ambulance, so I had to have my friends carry me out, it was a real pain in the ass.
IIRC, I couldn’t put any weight on it for about 2 weeks. Another 2 weeks I could put weight on it very sparingly. After that, I could walk on it, but I had to take a funny stance and walk slowly for another 2 months after that. Fortunately, it seems to have recovered 100%.
For those that sprain fairly frequently, check the bottom of your shoes. I used to be like that, and I finally discovered that I walk so that the outside edge of each shoe wore down, which made it more likely that I would turn an ankle. Now that I check my shoes after I’ve had them a while, and either throw out or resole any that start to look worn down on one side, I’ve not had another sprain.
Bad sprains take a long time to really heal. Light ones can be better in weeks. And yes, they can get colorful as the bruising makes it way out, which, for bad ones, might not be for a month or so.
My most embarrassing one was actually in a doctor’s office. My foot had gone to sleep, my name was called, and down I went! But I thought I had just twisted it, so did I say anything to the doctor? Of course not.
I sprained my right ankle really, really bad 4 years ago while out doing field mapping for a class. It was the first day out, I was going up this hillslope area that was a bunch of jumbly rocks. I slipped and fell, but caught my right foot between two small boulders. I feld the horrible crunch and this wave of pain came over me and I was laying there whimpering in pain (not to look like a whiny girl in front of classmates). My ankle started swelling, I could feel it, but the worse thing I could do was take off my boot. I Immediatly took some advil for the pain, because you guessed it, I knew I wouldn’t be seein’ any doctor (no insurance, no money). My professor asked if I was OK, I pulled off a pathetic “sorta”. I had to hike on it the rest of the day, that night he drove me into town (Ridgecrest, CA) to the WallyWorld so I could buy some first aid stuff (BenGay and and Ace ankle brace- whoohoo). That night when I finally took my boot off, my ankle was so swollen as well as lovely shades of black, blue and green.
Then I hiked on it every day for two weeks on rough terrain- no trails here boys and girls! One part of our area was a 2 mile hike in (everyday) just to get to the place where we could start mapping. I was quite pathetic. I ended up failing that class :o because I was in so much pain I missed a lot of details. I should have just had my boyfriend (now husband) come get me. I still have problems with my ankle off and on. Just last week I agitated the old injury by getting out of my husbands truck and stepping funny on my foot. 
I am such a klutz.