1997 Saturn SL2 I have an oil leak and a low idle

Engine Performance problem
1997 Saturn SL2 Two Wheel Drive Manual 165,000 miles

Alright so about a week ago my valve cover gasket blew out, it blew out at the first spark plug hole. So I changed it and when I did there was oil all the way to the top of the spark plug, so I sucked all of it out that I could get to but there was a little left that I couldn't get so I pulled the plug and it leaked down in to the combustion chamber. So could that do any thing bad to the engine or what? So then I changed the gasket and it is not leaking at all from the gasket! But after that I started it and all that day that I drove it there was white smoke coming out of the tall pipe, and the idle has been really low, it usually is at 1100 Rpm's but now it droped to 750 Rpm's. The white smoke went away after the first day but the rpms are still at 750, So why is that? And what was the white smoke from? And now it is leaking oil from somewhere that I dont know, any ides of where that could be or something that could have blow out when I changed the gasket? I also just checked the plugs and the one on the fare right end is full of oil and dose not look good at all! But the other 3 are still like brand new plugs, what dose this mean? And keep in mind that this car ran flawless before I blew the valve cover gasket!