I was attempting a "simple" oil change today. Ha! My frame sump plug got cross threaded/stuck and ended up rounding all the edges of the hex head. So I took it in to my LBS. He fixed it but I think (hope) he's removed the large nut & hose beside it whilst trying to remove it. I say hope because there is now a leak from that nut. Here's a photo of it. So the questions are: A) what is the nut attached to can I retighten as it is or do I need to do a full drain and oil change. It's a small leak - maybe 10mls or so in a few hours - but a leak that wasn't there before nevertheless. Thanks?!