How do I know if PicoSure Focus is effective for my cafe au lait macule? How do I know if I have a treatment resistant CALM?

Besides the obvious, which would be significant lightning—how will I know if the Picosure Focus treatment is effective? I am wondering if I have a treatment resistant CALM. I was first treated with Nd:Yag (532nm), but after a week my CALM reappeared. My second treatment involved the Picosure Focus. I was hopeful since the top layer of skin flaked off and revealed lighter skin for 10 days. However, it is past two weeks of my post treatment and the CALM is its original color. Please advise.