I Am 18 Years Old, And I Recently Gave Plasma.

I am 18 years old, and i recently gave plasma. During plasma my arm got really swollen and they had to restick in my other arm. After donating my arm was swollen and the next day it swelled down. But as the days progressed the swelling went away and I began to bruise all up my bicep underneath. Im not sure what the problem could be.