I'd lower the water so the frog doesn't have to put much effort into getting air. I'd remove decorations that may have caused this and keep the frog as stress free as possible. I'd also keep the water as clean as you can and perhaps lower the lighting down too so the frog can recover (do you have live plants?). These frogs can/will heal fairly quickly so this should not be fatal.

If you have a small hospital tank, that may be ideal.