A key consideration in medical procedures like thermal therapy is the danger of thermal harm to skin tissues from exposure to fluctuating thermal loads. To maximize treatment effectiveness while safeguarding healthy tissues, it is crucial to accurately anticipate and manage this damage, especially in hyperthermia therapy. The fourth-order Moore-Gibson-Thompson (4MGT) idea is employed in this study to lay a theoretical foundation for bioheat analysis. The purpose of this work is to clarify how skin tissues respond biothermally to varying thermal loading. The model developed makes it easier to anticipate the thermal reactions that occur in human skin and to estimate the efficiency of biothermal transfer in biological tissues. For the suggested model, a two-dimensional skin layer is utilized. The analytical results for tissue temperature are obtained using the normal mode approach. Both the impact of the duration of heat loading exposure and thermal damage are examined. Furthermore, the accuracy of the suggested model is evaluated by contrasting the obtained analytical results with accepted theories. The findings show that when the thermal relaxation time constant is included, the modified Moore-Gibson-Thomson biothermal model forecasts a decrease in temperature compared to the Pennes model.