I have used several yeasts that I thought smelled bad. I wouldn't say "rotten" but I really didn't like the smell. The beers were great.
Unless the yeast got really hot it should be fine.
I wouldn't worry about the fermentation for a few days. Your airlock might never bubble and your fermentation might be fine. Some fermentations do not create a lot of co2, you may have a leak letting it escape without going through the airlock.
Wait about 72 hours from pitching, then if you don't see any signs, like krausen or churning yeast, if you are using a carboy and can see the wort, take a gravity reading to see if anything is happening. Then you can decide what action to take. Maybe then pitching more yeast.