More On "Carbamide"

Urea or carbamide is an organic compound with the chemical formula CO(NH2)2. The molecule has two —NH2 groups joined by a carbonyl (C=O) functional group.

The term "urea" is also used for a class of chemical compounds that share the same functional group, a carbonyl group attached to two organic amine residues: RR'N—CO—NRR'. Examples include carbamide peroxide, allantoin, and hydantoin.
https://en.wikipedia.org/wiki/Urea

[Edit: Not to be alarmist, but I feel it would be irresponsible not to point out, given the preceding paragraph, that "DMDM hydantoin" does not function as a urea substitute in cosmetics, but as a preservative that works by breaking down to formaldehyde. As read on The Close Shave blog. Deemed safe by industry, info here.]

Urea dissolves the intercellular matrix of the cells of the stratum corneum, promoting desquamation of scaly skin, eventually resulting in softening of hyperkeratotic areas.

Urea cream is indicated for debridement and promotion of normal healing of skin areas with hyperkeratosis, particularly where healing is inhibited by local skin infection, skin necrosis, fibrinous or itching debris or eschar. Specific condition with hyperkeratosis where urea cream is useful include:

Dry skin and rough skin
Dermatitis
Psoriasis
Ichthyosis
Eczema
Keratosis
Keratoderma
Corns
Calluses
Damaged, ingrown and devitalized nails
https://en.wikipedia.org/wiki/Urea-containing_cream

So although I'll have to look again at whether "keratosis" might be that thing on my cheek, it seems like urea is more help for a different, drier kind of so-called sensitive skin, where the moisture has trouble balancing on the "exogenous pathway," through intercellular space in the stratum corneum. It looks like the mites and bacteria I was thinking might be important to my seasonal skin change are well recognized as factors here.
http://www.nature.com/jid/journal/v129/n8/full/jid2009133a.html

I know I probably make too much fun of the ashen-skinned fanboys of glycerine shaving soap. You can't ALL be unscrupulous, alcoholic psychopaths. For what it's worth (call it a "pee offering"): urine turned my skin back to summer soft.