nope. you are doomed. Try to reload a savegame from before the auction at the demon city or start from the very beginning.
Don't use Murphy's Hand. This artifact is only meant to be used as last resort for certain Bossfights. I never used it.
If it works only once it's hardly usefull. [Except Caro implements even more methods to reduce Corruption but that would totally defeat the point of corruption as game-mechanic.] HIGHLY Likly to happen: There will be more challgenes in the future game content the hero suffers corruption to get a rare item or beat a challenge or open a door or whatever-
It's better to restart now and beat the avaible cotent with a rather pure Hero than getting puniched a few update laters.
Murphy Hand was planned to be a last resort item against powerfull bosses. Now it has become a Newbie-Trap, giving experienced players a nice laugh: "Schadenfreude".