Cut big toe on meaty part. it's a large arc bigger than a thumb nail shallow to the outside and deep in the middle. how do i know if i need to be seen?

If you mean: that muscle, ligaments or tendons are exposed by the term "meaty" than this depth often warrants sutures. If the two sides of the laceration are gaping apart - then sutures may be needed. If you haven't had a tetanus shot in the last 10 years - you need one. If you were cut on a really filthy, rusty object than you may need to have had a tetanus shot within 5 years.