I was lifting in the gym and felt a strain in my abdominal area above my groin than a red puff marble size sore appeared it is going away. What isit?

Abdominal Fascia. Likely a small tear of your abdominal fascia has occurred. The raised area is either a small hematoma (blood filled sac) or partially herniated abdominal muscle that is pushing up and out through the small tear in the outer layer of the muscle fascia. Think of the fascia as a robust 'hot dog' casing that envelopes the muscle belly. Small tears should heal with rest and decreased exertion.