If it hits 20k I would expect a massive sell of from those who bought at 20k in December and are waiting to recoup if they haven't already taken a loss
This will provoke a fall in prices, but we have seen many times that after such kickbacks bitcoin easily captures new heights. Whales will raise prices to 30-35K dollars. Then they will sell their bitcoins and reduce the price to 15-20K dollars. They can always do it. But I am sure that the price of bitcoin will grow. Falling periods help to remove coins from the most impatient users.