if you've simply tightened the bb, in order i'd:
a) remove bb, clean bb threads and shell. reinstall using grease and teflon tape
b) if it still creaks .. remove the chainring bolts, grease, teflon tape and reinstall to spec
c) if it still creaks .. replace bb entirely
past that if it's still creaking, it's probably unlikely to be the bb, unless it's cracked.
i was once convinced i had a creaking bb. every time i stood on the pedals for about a month. it was driving me nuts. turned out to be a hairline crack in the rear rim. so as has also been posted, the noise isn't guaranteed to be coming out of the bb.