I would be hesitant to pitch through any joint pain because you may favor that joint at the cost of an adjacent joint. The ankle is a mobile joint. If you favor it, you will attempt to limit its movement. You then run the risk of trying to use the knee to compensate for that reduced mobility. However, the knee is a stabile joint - not a mobile joint. So you may end up with a sore knee too.
You might also end up altering your delivery and not in a good way.
Best thing to do is see a doctor.