Thank you. You said let it dry out unpotted. But where do I lay out the cactus specifically?

Trying to unpot and unveiled some rot on the bottom— is it a goner? I bought it a few days ago it must have been like this. I’m so upset.

Looks like rot to me - if it is, I would return it to whoever sold it to you (if possible...). What kind of pot and soil was it in?

Lining bottom of container with pebbles doesn't help - water just collects there and will cause problems by keeping everything wet. It needs to be in a pot with drainage hole(s).

If you unpot and bare root succulents, they can be laid on some paper towels or newspaper to dry up...

It was in one of those cheap plastic pots from Home Depot.... had drainage but I believe that it had been overwatered there. I have only had it for a few days and just noticed this. I took it out of its pot and the soil was a little damp. The roots are white and look healthy so i am hoping I can salvage it. I am now buying a pot with drainage, hoping that it will help. Once I repot it, I will not water it. Also I have a soil designated for cacti.

Also the spot that looks like it was rotting was just where the cactus had been cut prior to being sold

Soil designated for cacti is probably not well enough draining. Pls. get at least some perlite to add to it., and mix at least 50/50. It needs have very good drainage. Many of us grow them in inorganic mixes.

If the plant is cut, it should be left out of mix to callus. Bigger the cut, bigger chance of infection if stuck in the soil. And if kept wet, even more so. Plastic pot is ok - I have almost 200 succulents in cheep plastic pots that are recycled. Or get terracotta if you prefer.

Once you take it out, all old soil should be taken off the roots. But, if it is rotting, I would really return it. It is not fair to charge money for rotting plant...JMO!