Swelling after cast removal is very common.
It is caused by change in blood circulation during the period of immobilisation in the cast.
This can take upto 3 months to disappear completely.
Next Steps
Continue active exercises of the ankle and toes.
Increase your activity levels slowly.
Focus on proprioception during your physiotherapy sessions.
Consult your treating doctor for prescription or video consult with me if you have any further questions.