I would avoid using plasma pen in the areas where you might keloid. Typically, no one forms keloids on eyelids, so it could be used there. If you form the large thick keloids, I suggest avoiding it all together.
Plasma MD would be a good treatment for forehead wrinkles. It works by stimulating fibroblasts to produce collagen and elastin. It would not impede later surgery. Only Plasma MD is FDA approved.