Is my pressure regulator broken?

I had an Ar CO2 pressure gauge (https://www.amazon.com/dp/B06X3XWVYM/) hooked up to a valve that I was using to control the flow of 95:5 Ar:H mixture. After some overflows (i.e., the needle went to max multiple times), I heard a popping sound and now whenever I open the tank of Ar-H, the pressure immediately goes to maximum and I cannot control the flow rate. Does that mean my pressure gauge is broken or the entire regulator is? Thanks!

PS My regulator + gauge is this one: https://www.airgas.com/product/Gas-E…0aAimCEALw_wcB