Some of my friends and I were joking around, and I was playfully hit in the right arm. I noticed a quarter-sized bump where my arm was hit. A couple seconds later, it went away. I told my friend to hit me again, and he did. Another bump appeared, and again went away after a few seconds. We tried it on my left arm, and nothing happened. After a few more attempts, my arm started hurting, but no bruise ever appeared, just more of those bumps. I m just curious to know why I had large bumps on my forearm when it was hit! It never happened to me before, or anyone i know for that matter.