As others have said, work on the other arm in the meantime. It's not going to be load bearing for a few weeks but if you can get yourself into a position which a) isn't painful and b) involves a bass being in a playable position, you can at least do something. If you can realistically only use one arm then it depends which arm - if it's your fretting arm then practice fretting (I've seen a bassist whose right arm was useless due to a stroke, but he played very well with just his left hand) and if it's your picking hand then practice all picking forms - two fingers, plectrum, three fingers, classical guitar style.