this will depend on how many points it is dislocated at If your thumb is dislocated in more than one place you will need help as with any dislocation there is a risk of trapped nerves if you are not careful when relocating then you will really know PAIN the point of dislocation may be swollen, this might need an injection to re-leave pressure or the swelling. just to make putting your thumb back less painful and easier
While this makes the arm extremely mobile and able to move in many directions, it also means that it's not very stable. Most people dislocate their shoulder during a contact sport, such as rugby
You're just going to have to wait at the hospital until they see you. Someone with a dislocated thumb isn't going to be a priority if there are serious cases. Don't try and do it yourself, you could end up with a permanently damaged thumb.