I recently got some grimeca hydaulic disc brakes. I got someone to bleed them for me and before installing them, I somehow squeezed the lever and now the piston seems to be permanently closed or seized so that when i insert the rotor, the pads constantly rub against the rotor. I'm not sure what to do. I went to my LBS and told me I needed to rebleed the line. I'm a little skeptical about the mechanic's knowledge about disc brakes because he doesnt service them so before jumping out to do something, can anyone offer some advice? Any help would be really appreciated!