The start of this movie screams cheap family movie, cheap laughter and probably some youngster in the family might like it so much you will have to bite your teeth together and watch it time after time.
The “ugly” child is actually a cute girl with just a pig nose. So what we get is a very limited version of Shrek´s Fiona. I think that this is an obvious reference to teenage girls (but maybe also to a certain extend boys?) that are good looking but have one (1) part of their body they are not happy with, mostly without any good reason. (just a part of being a teenager maybe) And later in the movie it seems that my thought are just about right.
Now the good parts: The initial impression of the movie, while right, its done in a good way, although it fails to be hysterically funny, it has some nice touches and lines and at times almost an enjoyable watch.