The NOOK comes with a 1 year warranty.
If you got it last Christmas I would run (not walk) to the nearest B&N and see if you can get it replaced before the warranty expires.
If you take it back within 1 year of purchase, I believe you're still under the initial warranty. I'd take it back today to see if you can get a swap. This model has a history of screen problems that sound similar to yours. (I wouldn't mention the screen wipe.)
B&N had a bunch of old remaining NSTG (your model) on sale last week, so they may be out of the old model. If nothing else, they may offer you a nice discount on the new NGL model that's replaced it.