Hi, I am new to gardening in general and I have been taking care of an adenium for about 3 years now. It has been doing fine and has flowered the last 2 years but this year during its hibernation period the trunk started shriveling from the top. I know I am going to need to prune it back to fix it (something I have been hesitant to do before for fear of damaging it) but I would like to know if this is a sign of a bigger problem that needs fixing. Any help or advice would be appreciated :)

Picture below. The discoloured area is dry and papery and feels empty. The area below it feels fine. The roots are fine too. Nothing is squishy which is what I imagine rot would be like but I don't have much experience, just lots of internet research.