Seeing your son become a bar mitzvah is a proud moment for a father. But it can be painful too. Just ask Michael Douglas. The Academy Award-winning actor evidently partied so hard at his son Dylan’s bar mitzvah a few weeks back that he suffered an injury. Explaining why he limped into the recent launch party for Jerry Bruckheimer’s book, When Lightning Strikes, Douglas said, “I’m hurting. I don’t know whether it’s my groin or a hernia. I got carried away at my son’s bar mitzvah this weekend. You know they put you up in the chairs over the top – I think something happened there.” Douglas said he was going to the doctor Thursday.