if its actual leather as patent leather should be, could always try a spot of kiwi parade gloss boot polish.
those of us who are familiar with parade gloss would know its the basis for a good spit shine (oh how i sent many an hour shining my boots in cadets)
the first step of a spit shine is a small amount of parade glass applied and rubbed into the leather, before glazing over it with a lighter, but before glazing with the lighter the polish is dull and matte beyond belief.
if the boots are leather then this shouldn't effect the boots in any way, and after your con you can always finish the spit shine (gonna take a number of hours to finish btw) to get your boots back to the shine they had before if not better (spit shine done right can have a mirror finish)
and suggested before, always test this on the boots in an area where you wont notice it much, in case it does go wrong. all else fails see if you can find a place where you live that either deals with making leather products or shoes to ask for advice.