Originally Posted by Yooper
While it's true that 168 degrees would indeed denature the enzymes needed for conversion, it takes more than a few minutes for them to totally denature. Additionally, most grists will actually fully convert in 20-30 minutes so it's possible that you had full conversion, or nearly so if the heat didn't get to 168 until 30+ minutes into the mash.
I'd carry on, and be hopeful!
This. I'd also consider buying a cooler, that way you only have to worry about mash temps once.