I have a misdiagnosed fracture for sprained ankle on my cuboid bone for 2.5 months.it's 3.5 months & my foot start to get swollen much more. why?

Fracture non union: That fracture may be going into a phase of delayed healing depending on the treatment you've had thus far. If the fracture is not displaced, then you may benefit from a bone stimulator to expedite healing. Otherwise you may need surgery to address it.

Delayed Union: Many cuboid fractures are not initially seen on plain x-rays and their diagnosis can be delayed. Would recommend getting rechecked to evaluate healing (CT, MRI, and/or xray may be necessary). Also, would get your vit D level checked. Though rare with a cuboid fracture, swelling may also be a sign of a DVT. Get checked out. Good luck.