Sprains can take weeks-months to heal.
Swelling may persist few days, especially if you've walking on it & not elevating it as much as possible. Use ice first 24-48 hrs to help reduce swelling; then can try alternating ice & heat, but if swelling worsens, go back to ice. If swelling worsens or ankle becomes more painful, see pcp for further evaluation. May need airsplint or cast