To me it definitely looks like something is going on with that tail. I think I can see some unshed skin as well. Others who have experience with this will be able to tell you what to do.
Best of luck to you and your little guy! 
When I still worked with Cresties I had a ‘Pet Only’ boy who had something that looked like this and he ended up losing a 3rd of his tail by amputation. I’d definitely get it looked at by a veterinarian to avoid the risk of infections or possible necrosis of the tail, and to get it treated if there is something more going on here than a shed.
(Edit): Is this Crestie housed with any others? This could also be a sign of tail nipping. It happens very often with Crested Geckos housed together and can cause issues I listed previously. Their tails get injured by the nipping and darken and get crusty from the repeated healing/nipping process.
Ty for your help, and no she’s housed alone
That does look suspicious. I would take her in to have that looked at by a vet. If you happen to have pics of her which show the tail looking the way it did before you noticed the change, that could be helpful. Information about any changes in her appetite or behaviors, and when these were noticed will also be useful. If you haven’t already got an exotics vet who can evaluate her, this can help you to find one.
Best of luck. Let us know how things go.
Have you taken to a vet?
Tails defo been damaged, it’s a lot skinnier than the rest, looks like it’s dead or dying, so hopefully they’ll drop the tip.
Hey, yeah I took her to the vet and they amputated the part that was dead. The stuck shed cut off the circulation to that part of the tail. She’s doing good now and should be okay!
Awww! I’m glad you got her little tail taken care of! I am sure she feels a lot better!
Good for you, good for her! She is bound to be glad not to have a miserable tail dragging around behind her now.