I assume that by “endometrial biopsy” you refer to a minor procedure you did in the clinic, where your gynaecologist has taken a small amount of tissue from your womb lining for tests?
If so, the discomfort and blood-stained discharge usually clears within a few days. And you should be well within a week. If you are still experiencing pain or excessive discharge after a week, you must contact your doctor as soon as possible.
Your endometrial lining should fully recover once your next menses comes.
