Replaced exhaust tube and set torque per specs to 85. Since I never heard the "click", I'm wondering if I over-torqued the nut. Would it be OK to loosen it off and try again. Curious if this may have damaged the stud?

What size bolt was it that gave a torque value of 85lb/ft?

No way to say if you damaged the stud without knowing how much you over torqued it. 5lb/ft probably not a problem. 50lb/ft and you probably went too far. LOL