Well Today I Accidentally Bashed My Arm Really Hard On

Well today I accidentally bashed my arm really hard on a metal door. I was running ahead full speed and someone opened the door and it bashed my arm. It's really hurting now and it's really red. I don't know how serious it is and I'm worried since I'll be going on vacation tomorrow :( any tips or advice to make it heal quicker? And could the bone possibly be broken?