this is the property of your fascia or your muscle ?
you will need to resimulate your muscle system that's sure. For fasica/fat/dermal self-intersection isn't a problem because there is no collision on those layer. Fat collide with muscle but fascia and dermal have collision turned off so the fat can self intersect.
as i said zBones desactivate the collision when it has an self-intection and the only things you create as zbone and use as collider on the workflow is the skeleton and the muscle.
(as I've observed, two different object with intersection combined in maya doesn't created trouble)
some idea I've used to resolve this issu :
- remesh your muscle or just resculpt a little bit to add more volume or edges for having a better deformation
- add more or less ztets (more ztets will improve the curvature but can create some self-intections, and sometime it can resolve the issu)
- minimize the zattachement area on the muscle (sometime I attach only 1 vertex)