When a foolish person gains wealth suddenly, s/he might start to spend it ostentatiously and sometimes even talks rubbish. If such people get a powerful position, they might even abuse it foolishly. Such persons need not necessarily be evil ones, but the results could be because of their foolishness.
There are a few proverbs in Telugu language which translates to when a poor person became rich all of a sudden, he asked the barber to dress his hair at midnight.
To take one a peg lower - does this convey the appropriate meaning? What are the other English equivalent proverbs or idioms for the same?