John Elway's Son -- Photos of GF's Brutal Injuries ... After Domestic Violence Arrest

Jack Elway's ex-girlfriend says she's still traumatized from the violent attack she suffered at the hands of the former college QB ... claiming it was so brutal, she's still in therapy in an effort to move on.

As we previously reported, John Elway's son was arrested for domestic violence in Colorado back in May -- after allegedly attacking his then GF following an argument around 2 A.M.

The GF claimed Elway ripped out her hair and threw her to the ground -- and now TMZ Sports has photos of her injuries ... and it's bad.

Despite the graphic evidence, Elway was able to strike a plea deal in which prosecutors agreed to drop the assault charge against him. Instead, the 25-year-old pled guilty to disturbing the peace and received no jail time.