 [ Symptoms ] i use crutches after injured ankle and foot becomes very red and purple and my foot begins to throb [ Disease ] actually i am doubting the truth that your problem was only sprain of the ligaments but i suspect also fissure or fracture any way you should do an xray from ap and oblique views of the ankle the coloration should have had subsided with ice application rest and elevation  i recommend also an ankle splint complete rest and elevation you can use antibruising creams and reparil tablets for the swelling twice daily