I sprained my ankle about a month ago by simply stepping off a treadmill and hitting wrong. My foot rolled inward, I heard something, and immediately, and for about 3 days afterwards a wider than a golf ball size lump was on my outside ankle. However, I could walk around without too much pain. I iced it for a couple days, the swelling went down, but not all the way. Now a month later, the ankle is still slightly swollen and I have constant tingling/numbness in my foot and all the way up my leg.