Those spikes aren't normally enough to kill the embryos. You should be fine. If you want help stabilizing your temps, give us some details about your incubator setup and you'll get more advice than you bargained for 'cause everyone on here is so helpful.
I had a temp spike of 105, and it looks like they might have survived it. That being said, I'm not sure if it was the bator or the thermometer that spiked. A reading that wasn't quite true might have done it too....new thermometer....
My crazy Fluker's thermo/hygro spiked to 126 right in front of my eyes. I knew it was not even possible since we had been doing something with the bator and were hanging right there when the reading happened. Good thing, too, because if I had looked at the minimum/maximum and saw 126 degrees, I'd think they were all dead! Don't ever throw out eggs just because you think you had a spike (if you are going by min/max on the thermometer).
First of all, what's your thermometer setup? Are you using a good, calibrated one and is the probe in a water wiggler? If not, then you may not really be having temp spikes, your thermometer might be having issues. Test your thermometer and get a water wiggler or make one out of a baggie. Second, Is your bator a still air? If so, then your temps should be at about 101-102, so you're fine. Next, your bator should be located in a place that has stable temps. I use a closet that stays the same temp all the time. Also, you can add a jar of water with a lid to act as a heat-sink, which will help stabilize your temps. See if you can get your temps stable with these suggestions. If not, let us know what's going on and we'll go to phase two!!