The very general advice I've been given is to coddle joints, tendons and ligaments like pampered princesses, and to treat muscles like dirt.

Of course, an actual tear or something you let the damn thing heal - but if you've just overdone it a bit, you're better off better pushing through and using it normally.

Most of the pain from day-after-workout soreness is from swelling - the muscle bundles get a little frayed and leak fluid into the sheath, and it's the pressure buildup that causes the pain. If you walk on it anyway (or equivalent), you gradually squeeze the fluid out, and it becomes much less complainy (until you rest for a few hours and it fills back up again).

At least, that's what I've been told, and what I've noticed in my own experience. This is not medical advice.