I have a skin graft to my right thumb which is irritated if I use my right thumb without a thumb pick so can I use a thumb pick for the above?
I reckon you can do what ever you need to do to move forward. Perhaps you can modify the pick a bit, shave it down, take the edge off, or what ever–experiment–to help produce a softer sound. Maybe a bit of duct tape on the pick? glue thin rubber or latex to make it 'thumb like' feel.
A while back I had a nasty splinter under the thumbnail right where it hit the strings, and so I began to use a thumb pick. I just got used to it, without modifying it. Then the splinter–and the pick–went away. But though it was awkward at first, it was not hard to become accustomed to. I also use a smooth plastic Fred Kelly fingerpick for frailing, and it makes the notes clear, as I have papery and noisy nails on my fingers.