how is your mobility etc?
I did that last year, swollen an inch in circumference, the whole arm. I had to go through about a month of PT but was riding the weekend after I injured it
Try to keep the arm moving idk if youve been told... it will help move all that blood out, mine too was from my armpit to my wrist... it looked worse near the elbow/forearm though and I had some shoulder trouble... which was why I had to do PT. Do that PT... it will help your riding making you stronger anyway, and get back on the board asap! I was jumpen cliffs and wakeboarding the next week even though I probably wasnt supposed to. Suck it up
you'll be riding in no time