I think we've broken the H&S, and drop seems unlikely. The market seems convinced that the stock is worth $18-25 no matter what, and FB met all revenue targets so far. If it was going to fall to $22, seems like it would have done so this week.
Now FB has to show that they can host a media event with some real confidence. This Android partnership could help a lot next week. If they can manage not to completely blow it - which they usually do - the next few weeks could move the stock back up to $29 easily.
Let's hope that Sandberg knows that if she wants to make an impact with the public, she first has to convince everyone she knows what she's doing as the COO of the largest social network.