loosen the bleeder while you screw the caliper piston back in. it'll squeeze some fluid out, but opening the bleeder will relieve the pressure a tad to do so. also get the biggest flat screwdriver you can find (i have a 3 foot beast) and put between pads and pry open and try to slide it over the rotor.

might have to bleed that individual brake if u open it up but it works way easier than trying to do other stuff.

also invest in the caliper piston turning tool....WAY easier than using sawed off old needle nose pliers to try and turn it

as much as i absolutely HATE brake jobs, i have become a master at them...so i dont have to spend as much time with the bloody things.