i would advise against it, the way in which dnp works would not be coherant with topical use.
time to get technical....
*DNP accomplishes the astounding boost in metabolic rate via inhibition of the F0F1 ATP synthase molecule, located in the inner wall of each mitochondrion. While the electron transport chain still functions to pump hydrogen ions into the intermembrane space, the coupling of the proton gradient to ATP production is rendered impossible by DNP. As a result, ATP production is dramatically reduced, and the energy is instead thrown off as heat. This results in an astounding production of heat; when using dinitrophenol, the athlete will radiate so much heat that it is uncomfortable to be within any proximity of them. Luckily, this heat does not fully contribute to body temperature increases, and is instead thrown off from the entire body surface, particularly the head. As a result, adequate doses of DNP will usually only elevate body temperature by about 1-1.5ºC. This is a good thing for your central nervous system and other delicate tissues; if the heat produced by ATP contributed in a more direct matter to body temperature, effective doses for fat loss would cause supraphysiological body temperature increases on a level unwitnessed at this time.*