Hello,, you are taking treatment for filarial parasite infection. Infection of lymph vessels by it causes blockage of lymph (extravasated plasma to tissues) drainage back to blood vessels through lymph nodes, that causes swelling of organ which are drained by thar lymph vessels. Once you start treatment it improves very slowly, since you are seeing you need to wait for another few weeks to totally resolves (some times some swelling will not regress if infection is very long standing).