What happens when the drain doesn't work? What's next?

I went to my 13 day check up with my doctor and he found a small fluid pocket, he dained it with a syringe and placed a drain. It's been 48 hours and there is yellow fluid in the tubes but nothing hit the bulb. The nurse said the little that was pulled with the syringe wouldn't be noticeable. What happens when the drain doesn't work? Is there anything I should or could do?