How can i stop ankle swelling?

It depends: Swelling can be due fluid retention and can be due to medical reasons, medications, excess dietary sodium intake, and other reasons. Dealing with those issues can resolve the ankle swelling. If the swelling is from the ankle joint, it might represent an injury or arthritis.

Need to find out why: Need to find cause so it can be properly addressed. See physician. In meantime elevate and try compression sock.

RICE: Rest, ice, compression , elevation.