What Causes Bruised Bicep After An Injury?

I fell very hard one week ago. I slipped on ice and went down on my left arm/shoulder. Huge amount of pain. ER exam and Xray showed no breaks. I had no apparent bruising at that time. My bicep started to bruise three day later and now it s almost covered by a huge blackish bruise extending from above my armpit down to almost the elbow bend on front of my arm. Should I be concerned about blood clots? The pain is not as bad as the night I fell and range of motion is starting to return, although slowly. I cant raise my arm from my side outward, although I can do everything painlessly from my waiste down