The sparkling dust from the caustic wastes will quickly react with exposed tissue. Superficial skin burns are squamous, taut and clearly delineated, with a greasy sheen and blue to violet pallor. Prolonged exposure can easily lead to a runaway reaction which burns through tissue, leaches into the blood stream or eats away at organs.
Deeper burns are particularly difficult to treat, especially since the end of the world destroyed most of the civilisation's capacities for high-level health care. The immediately life-saving treatment still somewhat available involves introducing a complex medicinal compound to the reaction which, if successful, causes the harmful substance to expand and crystalise, rendering it largely inert in contact with tissue.
These crystals have a similar hardness to Hssken teeth or quartz, and can be carefully filed down or drilled into with similar (although rarely available) techniques. They do not shed if embedded subdermally, and generally prevent organic tissue from growing in place or healing up the affected area. However, having crystals hold the patient's digestive tract in place is often still preferrable to multiple organ destruction.
Crystallising caustic wounds is a tremendously painful process which requires a skilled practitioner to ensure that at least a modicum of flexibility is either still available or can be restored (e.g. by ensuring gaps for muscle expansion or future growth). So of course there is an entire cult around deliberately exposing yourself to the dust and turning the embedded crystallisation into part exoskeleton, part in-group status symbol and proof of the amount of pain you can endure.
