That was the weird part about it, It didn't hurt at all when I failed on that rep and I heard no pop or sharp pain at all. I even finished my workout with straight leg deadlifts and hamstring curls and had no issues. The only thing I could think of was that maybe its just a bruise caused by the hamstring curl machine being tight on my leg when it locks into place but I don't know how that would cause a lump like this, its the size of a golf ball.
After a couple days the lump completely went away. Then after yesterdays workout it was worse than the first time and the bruise set in more then. I still have no pain or lack of motion/strength from it. I googled the hell out of the symptoms and have found nothing.