Nice results, looks very interesting !
Regarding pressure attributes I would suggest to ramp them up, from 0 to 1 on zTissue node
If you are already doing this, increasing substeps should help, just to create fascia layer mesh I would recommend to increase it to, at least, 10. Also you could decrease the value of collision point spacing on zSolverShape node
If you can still see issues try lowering pressure values ( your current values look fine to me )
Hope this helps !