The scaphoid is a bone in your wrist which lies underneath the little dimple at the base of your thumb. nice wikipedia link
Injuring yourself in the way that you did can cause an injury to the scaphoid that usually does not show for 10 days or so. What happens is that the blood supply has been interuppted and the bone will die back a little bit over a few days leaving a hairline fracture visible. If you poke in the dimple and have to be peeled off the ceiling, then you probably have broken it and it isn't showing yet!
They should give you an appointment for a review clinic in 10 days to 2 weeks time from the injury and then re-xray you to see if there are any changes visible.
If you have fractured your scaphoid, it will heal again - it just takes time, 6 to 8 weeks or so. They may keep you in the splint or upgrade it to a cast.
It is a very common injury, but good enough to get you out of peeling the sprouts and washing up this year.
Hope you feel better soon.