It's possible the stitches are the type that fall out on their own after enough time goes by. Mine were like that, but that was for a partial glossectomy. The answer to your question might be located in your mom's discharge papers.

The number of people involved in my care (@ a CCC) is humbling. Doctors, nurses, therapists, support staff, & of course, family. With everyone fighting for me to beat cancer the least I can do is fight back and win!