Ouch. Sounds like you overdid it! What you have is a little blood blister. The best thing you can do is leave it alone and after a few days it will disperse on its own. Don't try to pop it or squeeze it as you will only make it worse. If you pop it you will have an open wound and that will be very susceptible to infection. If it starts to itch or smell, go to your doctor straight away - they won't need to know all the gory details, but they will be able to give you some antibiotics to treat any infection.
Pull a Lorena Bobbittt-cut an inch or 2 off that puppy !A little shortnin' bread,if you will !NO------no not even lance it.Soak in a little Peroxide topically for a few sec.,to sterilize,and soften.It might even soften enough to leach the blood out.If so,wash gently with disinfectant soap,and paper dry,and LEAVE alone !That should fix her (whoops-him) up.
Penile hematoma can be self treated within few days. You should do not pop up the hematoma and wait for few days. For details, visit this link.