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.
