Bruising easily should not be a side-effect of Opioid use. I'm not saying it's impossible, but it's definitely not reported commonly. I'm with T. that you might have just banged yourself up a litttle while intoxicated? We often don't realize how intoxicated we are, sadly. Easy bruising however, can be a sign of serious medical complication, like liver damage for instance. Do you have a PCP you can check in with?
It's my personal opinion that the two phenomena are unrelated, but it's just a guess.