No matter how much you sweat, the humidity overrides the cooling effect of sweat evaporating.
Even worse than that. A living human must have a skin temperature of no higher than about 37 ° C. When the dew point temperature is higher, this means that the humidity condenses on your cooler skin and delivers condensation heat - the opposite of the process of cooling by evaporation. You can see that in a Finnish sauna for hot, short periods (where the body core temperature is not affected because it is short).
But the body has no means to get rid of heat. Over a longer time, you would be cooked alive. This is why high dew point temperatures are deadly and not survivable.
Even worse than that. A living human must have a skin temperature of no higher than about 37 ° C. When the dew point temperature is higher, this means that the humidity condenses on your cooler skin and delivers condensation heat - the opposite of the process of cooling by evaporation. You can see that in a Finnish sauna for hot, short periods (where the body core temperature is not affected because it is short).
But the body has no means to get rid of heat. Over a longer time, you would be cooked alive. This is why high dew point temperatures are deadly and not survivable.
See this table:
https://en.wikipedia.org/wiki/Heat_index#Table_of_values