I was rolling with a guy last Sunday, and I noticed while we were rolling my arm got stuck in a wierd position where I felt some shearing pain for a few seconds. I noticed later that I had a giant bruise with purple stretch marks on my right bicep. I think it might leave a scar or two, perhaps I should leave my gi on next time. Or I might by a rash guard, if I can find a good one. Does anyone have any similar experiences or advice?