After taking provera (medroxyprogesterone) for 10 days, how long do you bleed afterwards? I am bleeding heavy now. Haven't had cycle since nov 2013.

It varies. This should be viewed as a period, even though it has been brought on artificially. A normal period can be anywhere from 2 to 10 days. In your situation there has been a lot of time for your uterine lining to build up, so it is not surprising that this bleeding is heavy.
4-5 days. Sometimes longer. Are you taking prover for 10 days or depoprovera every few months?