Going to get thumb-size mole checked. I'm very tense person due to spasticity. Should I take muscle relaxer? Would that interfere w/med used to numb?

No NO. Exactly what do you mean by "muscle relaxer"? No you will not need a tranquilizer. No, it will not interfere with local anesthesia. You do not yet know if any procedure will be done. It will not hurt. Relax.