I've tried this before, in the past. I dabbed some toothpaste on a few big pimples before I went to bed (and put a towel on my pillow at night... unless you want some toothpaste on your pillowcase).
A) If you put too much on, it will burn. So if you DO try it, don't put it on just any skin. Only put it on the pimple area.
B) It did dry out the area within a day or two... however the result was a peeling and dry mess. I was worried about scarring so I didn't try this again.