What are good erb's palsy exercises?

I got erb's palsy when i was born,Even though i got a suegry at the age of 8, I can't lift my (Left ARM) all the way up like my right arm. I started working out about 2 months ago and i felt my arm more physical movement. I am currently 17 and i want to become a professional Boxer,so please....anyone, out there would happen to have any advise in this particular subject i would sincerely appreciate your time...all of you. Thanks Ladys And Gentleman an so long.