I suffer from plantar fasciitis off and on along with a heel spur.  While I have not had the numbness you describe or peeling skin, I have found that the only way to keep it at bay is stretching on a daily basis.  I am very conscious about sleeping with my foot flexed instead of pointed, definitely flex before getting out of bed and keep feet in a more flexed position than pointed when sitting.  Plus I always warm up and stretch before Crossfit workouts and definitely stretch after.  Oh and I also have custom orthotics in my sneakers and try where other shoes/sandals with an arch support.   I never go barefoot and at the doctors strong recommendation, stopped jogging.  Lastly, if the heel starts hurting and looks inflammed, I try to roll it on a frozen water bottle.

Hope this helps.