Pam's mom made her first appearance when she visited her daughter at work but wasn't seen again until she underwent massive plastic surgery, lost a couple of inches in height, and went from looking like Cochran to Purl. And nobody said anything. If our mom showed up to our wedding as a completely different woman, we'd have some questions. One, where did you get the money for plastic surgery? And, two, who are you and what have you done with my mother, you monster?
Yeah, we get it. The first time we saw Pam's mom, Helene, was in season two, and it wasn't until season six that we saw her character again. We guess actors don't hang around for four years waiting to be called back on set.