I dont think that it will get back to $20000 again, but all those who sold before are now buying back, so yes, the huge marketcap that bitcoin lost yesterday is going back to bitcoin again.
Maybe it wont touch $20k, but $17 - $18 thousand dollars are a realistic price.
I don't see why it won't go back to the long term trend. I mean, the rise in bitcoin prices was never a bubble, its all about the rising difficulty. Also remember the last time it crashed $18k to $14k and people said it could never go higher than $18k (this happened less than a month ago), but than bitcoin prices not only rapidly recovered but they exceeded the $18k threshold and hit almost $20k. I see no reason as to why a similar thing to this will happen again before year end.