Study on the internet about the 5 Day Extended Patch Test, yes it is a full 5 days unlike the environmental test you have already had. I've had the True Test 5 Day Test twice. The kit is extensive, around $1,500 but Medicare covered it based upon my severe symptoms.
Once tested you will be given an id # so you can go to the ACDS Camp list program on which your doctor will have you registered with all your allergen's. This Camp list is updated every year and it lists products which do not contain your allergen's. It's a good starting place. It's the only reason I've actually found certain make up and grooming products safe for mel. Unfortunately sometimes I react to products which should be safe because they don't contain my allergen's yet I think that's because I wasn't tested for their additives, or I became more reactive over time. So still go slowly with new products.
I understand what you describe as little white bumps which are under the skin. These bumps are just dormant GD, waiting to explode. Mine are confined to my upper and lower back now and not the entire torso (except th sides and breasts which never had GD. If I go outside in the heat and sweat I can feel them get larger, but if I stay cool for a few days they will recede and not turn into a papuale. However mine have been dormant for so long they do not itch or hurt. The pain took over a year to go away even after my outer skin was totally healed. We're simply damaged.