Oil plug fell out on the highway, oil change people admitted fault, what do I do?

I got my oil changed last Wednesday and today (9 days later) on the highway on my way to work I hear a thud, and then I see smoke billowing out the backside of my car. I drive about a mile or so more and then pull over after the oil light comes on. AAA tows me back to National Tire & Battery who admits that they didn't tighten the plug correctly. The car seems to be running fine now, but what if my engine is screwed up? Should I do anything else?