Do soma's show up on a hair folicle test?

If they are looking for muscle relaxers they sure can.

As J9 has mentioned, it will depend on what tests they are doing, but if they look for it and/or if it is included in the tests ran, yes it will show up.

Drugs are incorporated into the hair shaft from the bloodstream, so that being said, Yes. Even new hair growth for the next 90 days will have trace amounts of the drug.