Don't need to get rid of it, just either fill the holes with aquarium sealant, or leave it out until the snake is FAR too big to fit in the whole (then wait till it gets a little bigger yet!).
The reason probe thermometers are so much better is that they measure the temperature exactly where you NEED to measure it...at the warmest spot the snake can reach. I dare say your snake won't be spending much time stuck half-way up the glass on the back of the tank, but it WILL dig down and lay right on top of the glass over the UTH. IF you don't know that it's too hot for it, you can't regulate it properly, and unfortunately, your snake might not realize it is too hot until it has become injured, perhaps fatally. Conversly, if it's too cool, it won't be warm enough to properly digest it's Mouseburger, and will end up throwing up (regurge) which is equally detrimental.
I noticed that it looked like there was something packaged in with the UTH, or was it just a fake rock sitting on top of it in the picture? IF that is a 'hot rock' that plugs in, take it back. Those things are notoriously bad for snakes.