What would you do?

Okay, probably only the mothers reading this will understand the question I am about to ask and not be too grossed out by it!

What do you do when you put your toddler down for his nap and you realize that he has a huge poop in his diaper after he has fallen asleep??? Austin played for a while after I laid him down and I even heard him yell my name a few times but I didn't go check because he tried this little ploy the other day to stall on going to sleep. He settled down and went to sleep so I didn't think anything of it. When I walked by the room he is in (we are visiting at my Mom's right now), my nose caught the odor all the way out in the hall! Well, I do have a sensitive nose, but that is still pretty bad. So, now I feel terrible!!

Do I let him sleep and enjoy a little peace or do I wake him up to change him???? What a fun dilemma I am facing right now! :) What would you do?