had a mechanic put on new break pads about a month ago. my rear brakes stopped working the other day and i looked at it after a day and a half of riding on it like that with them working every once in awhile. they messed up and didnt either put locktite or dindnt torque on one of the bolts that holds my caliper on. my rotor looks messed up. is there a good possibility that the piston grinded on the rotor creating divots and now i need new rotors? this is for a motorcycle but i think the brake system works the same