If I continue to walk around on a tore pcl, will it cause more or long term damage?

No. Most PCL injuries are minimally symptomatic so simply walking around shouldn't be a problem. Pcl deficient knees are weakest or most symptomatic when going up and down stairs or hills. You can minimize this with a good rehab program which would include quadriceps strengthening.
Usually not. If you have instability symptoms with activities of daily living then damage may be occurring. Most isolated PCL injuries do not lead to long term damage.