Dyntopo Stops Working

posted to: Caricaturing Hair

In the middle of sculpting the hair, dyntopo just...stopped working. It worked fine when extracting the first three pieces of hair, but the fourth is not generating new topology and ends up being a real bizarre low-poly thing. Detail flood fill works, but any new sculpting does not create new topology. I have tried quite a few things, and nothing seems to be working--any ideas?