One of the long-term objectives of this study is to be able to act quickly on body burns, to avoid propagating lesions due to heat diffusion. An experimental and numerical study is presented to better understand the thermomechanical behavior of the skin and its direct environment when exposed to strong thermal variations. The experimental step, suggested in this article, consists in placing a cooled cylindrical steel bar on the skin of a human forearm and measuring the temperature change using an infra-red camera. Blood circulation in the veins was seen to clearly influence of the heat diffusion. These experimental measurements provide a numerical model of the skin and its direct vicinity. This two-dimensional multi-layer model uses the Pennes equation to model biological tissue and the equation of heat in a fluid, to model blood. The properties of materials from the literature are validated by experimentation. The numerical model is able to simulate the experimental observations, but also to estimate blood speed in the veins.