Regulator malfunction...is it shot?

Installed a second regulator on the setup a week or so ago and was leaving it under pressure (about 10 psi) to test. Tonight as I tried to adjusted the pressure upwards CO2 exploded out of the back of the regulator out of the hole where the spring relief valve is visible. As I tried adjusting the screw on the front to see what would happen CO2 started rushing out of the screw housing too. Any ideas what happened here? I'm guessing this regulator is kaput.

Diaphragm failure would be my first guess. You can try dismantling it and see if there is something stuck or if the diaphragm is cracked. Some regulators you can get repair kits.