is a common infection. Draining of the abscess is a complicated procedure and has to be done carefully. Proper antibiotics and analgesics after draining will completely heal the infection. Please continue your sitz bath.
A fistula if present will show some draining of pus. Please ask your doctor if the fistula is intentional for draining of remaining pus. If so , you dont have to worry.
Wishing you a quick recovery