Ruptured Ovarion cyst

In September i was diagonsed with a ruptured ovarion cyst they said it was 0.5cm. How can the doctors tell what size if it had ruptured. And how long does it take for the ruptured cyst to finally go away. I didn't really have any pain i went to the the er one day cause i was really dizzy and my abdomen was a little tender and thats when they discovered the ruptured cyst so i don't even know when it ruptured. They discovered it through a tranvaginal ultrasound. So does a rupured cyst ever go away.