Panic selling and why is the moment to buy

since 2 years now, the bitcoin and other currencies exploded and taken a solid position with 880 billion dollars market cap in december 2017, while the pump and dumps affect the market but not so much (since the pumps can be done only with smaller currencies), there is another problem that affect this crazy market a lot more, the information from institution, like the korean ban the other day, or the china one in august, this always let price go down suddenly, and create panic, the thing is even with this clear 20% loss on almost all the major currencies, you would have done anyway a big profit and could stay in the game withouth affect the prize when will it bounce back now?