Of Chinups and swollen biceps

Another crazy idea. decided to match my fitness with another dude today . We started with the chinup bar . The other guy did 3 X 10 chinups with a reverse grip . It seemed pretty easy to look at , and against my initial judgement went ahead with the exercise and ended up with 3 X 6 chin ups. It seemed fine initially with a little niggle . The trouble started in the evening when I was reaching for the bike handle , only then did I notice the swelling and now I am walking like a la Salman Khan - (minus the muscles )