In case anyone else has this problem.. I updated to 18.104.22.168, then got a "kernel panic". Couldn't boot the new kernel at all.
I discovered an easy fix (though for all I know, you all already know this. In case you don't, or are a noob like me, here it is)
*insert magical super user password here*
yum remove kernel (insert kernel version here, in my case 22.214.171.124.fc16.x86_64)
(asks if you wish to remove kernel y/n)
then use update manager and re-install new kernel.
Step 3: Profit!