Hi Sam,
These are tough lesion to treat.
I have treated them with a FRP Nd:YAG, but I think CO2 would be better. No laser “cures” these….yet.
I would try using the erbium w/o water defocused and with “light” air. See if you can remove the surface epithelium and get down to the basement membrane and put an thin eschar. Try a test area and document the location so you can track results.
Let us know.
Bob