Tweak CAD design for product

I have a CAD design for a thing I am making - a small container on a necklace. The design itself needs a few more tweaks before I am ready to move forward with it. Specifically it will have to be designed to engineer with a plastic inside and a soft, rubbery silicone outside. My current CAD doesn't have those specifications - I am looking for a designer with experience in product design and manufacture who can edit my current design accordingly.

Thank you!