On the bright side, eggs tend to handle lower temps a lot better than higher. You can moisten a paper towel with tepid water, wring it out, then drape it over the eggs. If they plump back up after a day or two, that'd be a pretty good sign they're still chugging along. Don't lose heart if they don't though. Some eggs dimple early and hatch just fine. There's no harm in continuing incubation until you're 100% certain. Unless the smell is overbearing and they're molded and I can't candle veins, I give eggs a chance.