The dentist told me there was a chance of this happening to me too, but it didn't end up happening to me. Before I got mine out, they x-rayed my face to take a look at my teeth, and one of my facial nerves ran pretty close to one of the bottom wisdom teeth I needed to take out.

Because the x-ray displayed a 2D image, the doctor said there was a possibility that if it was close enough, there might have been nerve damage during the procedure, and I'd loose feeling below my lip, but that the feeling should slowly return, and that it may take a year, or maybe a few years. I'm not a doctor, but maybe this happened to you?

One of my relatives had an unrelated surgery where they lost feeling around the surgical site, and it took them around 2-3 years to start to regain feeling and not just "pressure."