I thought I only sprained my ankle two weeks ago, but above my ankle I keep getting a sharp pain like a foreign object is in there stabbing me every step I take. My leg is swollen about an inch larger than my other, but the swelling goes down overnight. Within a couple of hours of hobbling around the next day, even with it wrapped with the ace bandage, my leg swells again. I haven't seen a doctor. I've had many sprained ankles before and thought I knew it was only a sprain this time, too. My husband says I'm only holding water and that's why it is swollen. My other leg doesn't swell above my sock, which also have a crew neck tighter than the ace bandage. My foot also swells and is painful to touch as is my leg above my ankle and my ankle, too, of course. It's hard to get to a doctor. I'm the caregiver for my husband's 91 yr old mother.
Your leg will swell when fluid can't get out of it which could be due to a myriad of reasons. If it's decreasing when you're horizontal at night, it sounds like blood or fluid can't fight gravity.... this is directly after spraining your ankle, so it's most likely trauma related.
Difficult as it may be to get to the doctor, you really should. I don't think it's broken (I highly doubt you'd be able to WALK on it if it were, but you never know), but it could very well be damaged muscles or tendons. I'm wondering if you've pinched off veins and/or lymphatic vessels .... enough swelling CAN do it too.
Broken or no, you may need crutches to allow your leg to heal. Please see a physician?
Good luck and keep us posted!