Never buy for a "quick profit", especially on such a volatile stock. There's going to be a lot more roller-coastering over the next couple weeks with earnings report coming out. In the end, it will revert to the mean and share price will depend on fundamentals - with those fundamentals still exploding, price will go up, on average, over time. I bought some more at $619 today, and yes, it's off another $7. No big deal. Fair price is probably 18x earnings, which would put share price around $740 (and higher still after upcoming earnings release.) Right now, trading at around 14x earnings, which is ridiculously low.
You're never going to find the bottom, or the top. And getting excited over a less-than-1% difference just isn't worth it. Especially considering the 52-week-low was $363 late last fall.