A skin burn model using variable thermophysical properties as a function of water content is studied as it is subjected to a heat flux at the skin surface. The model employs the finite element method to solve Pennes'  bio-heat equation as it is subjected to heat fluxes modeled from actual sensor test data. The model assesses burn damage using the burn integral of Henriques  using burn-threshold criteria Ω at both the epidermal-dermal and dermal-subcutaneous tissue interface. The model's times-to-degree burn, cumulative burn damage Ω, and peak temperatures are studied as the blood perfusion rate and water contents for the respective layers of skin are separately and arbitrarily varied. Results from the variable- and constant-property Pennes' models are compared.