Yesterday, was working Bi's. Didn't do anything out of the ordinary, but I did switch to low weight Hi rep for this week. Got a nice pump. Get home, and my Bi feels like it had Indian burn. Wake up this morning, my skin is tight and I have a warm buring sensation. 4 hours later I have a line that starts from insde my armpit all the way around my Bi to the inside of my elbow. Perfectly outlining my Bi. Stretch Marks maybe? My arm has been an inch bigger in the past and stretched more than yesterday so I don't see how I got it. Pic for reference. Not me, just an example.