Staying in a hot tub for 24 hours could be deadly and even if not then it's still not good for your skin or your health.
If you stay in a hot tub for even a few hours your core body temperature will increase too a high enough temperature that could cause you to lose consciousness and then if you're not removed from the hot tub you could die as a result.
Essentially when you stay in a hot tub for 24 hours you're gonna suffer a heat related illness such as heat stroke and die.
When using a hot tub you should not stay in the hot tub longer than 10 minutes at a time but if you do want to stay in the hot tub longer than 10 minutes make sure to never go longer than 30 minutes.
If you start feeling dizzy, faint etc then get out of the hot tub and cool off for awhile before returning to the hot tub.