Nothing ventured, nothing gained, right? Even if you end the month 49,000 words short, that’s 1,000 words you wouldn’t have otherwise.
Consider the word-count goal a threshold, not necessarily a stopping place. Reaching that goal and realizing you still have a lot of wrapping up to do is a good thing: it gives you something to come back to and work on later. You will still win if you reach your goal but have not yet “completed” your novel. Keep writing!