For many of us here, myself included, the skin disease element of PsA is of lesser concern to us than our joint disease and perhaps we don't even see a dermatologist, our skin being treated by our general practitioners or our rheumatologists.
I was recently asked about my own skin involvement by a new doctor and was shocked to discover that the psoriasis on my feet, at it's worst, was in the severe to very severe classification. And of course, it waxes and wanes, Sod's/Murphy's Laws dictating it will be waning whenever we see a medical professional!
Here is a pictoral scale which you may find helpful when discussing with your doctor:
This is an extract from https://www.psoriatic-arthritis.co.uk/Assets/Files/Content/PsA%20Training%20Manual.pdf