http://www.creationkit.com/SetLevel does exist, but the game world isn't adjusted by using that function any more. You might need decrementPCSkill instead, which doesn't exist, so you'd need to ask the SKSE guys to add it.
I don't need the game world adjusted since my mod will replace the character's level back to what it was anyway, I just need to be able to strip their level so they don't double their level through my mod.
How exactly would I use the SetLevel function if it's still in the game? Or are you merely talking about the Console Command which is of no use to me in this situation?
And again, if anyone could point me toward the direction for information on using SKSE as a modder with a function reference, I would be most appreciative.