Just to build on Highglyder's comment, I don't know of a way to accurately gauge pain. The best we can do with something like the Borg scale is compare a patient's pain to what it had been.
Too many variables. Anxiety plays a large role in vital signs. Treat what your allowed to. Looking at the splintered end of bone through a leg, sure. Treat the patient, not the vitals, unless they're compromised internally. They'll get plenty of candy at the receiving facility.
"Cooler than a cucumber in a bowl of hot sauce."