Shouldn't even warrant the question, just get the iPhone replaced and move on. Yes, it looks wonky and you definitely SHOULD get it sorted, by way of warranty. It may not be the screen, it could be caused by a dislodged mounting or some distorted internal component, but regardless of what it is, that's merely academic, it's wrong, needs fixing, end of.
Anyone who says otherwise is obviously happy to adopt the 'it'll do' attitude, which really is a poor show.