Get it checked out. I blew my knee on my first day back in the dojo Sunday but that was the ACL again. Dang dang dang Spent a couple days barely able to walk. Slowly getting better now.

RICE helps and can't hurt I think:
rest
ice
compression
elevation .... or is that

rest
ibuprofin
compression
elevation?

Yes to the stretching and foam roller. But get it checked out for sure.