Suggest Treatment For Purple Bruise On Upper Arm

My husband has a purple bruise on his upper arm from a recent car accident. I was in the car with him and neither one of us "hit" anything. This bruise has straight lines in it. The lines are the same purple as the bruise. we have been icing this. Do we need to worry about the straight lines. I have never seen these before..They go from side to side (not up and down). hank you!