One of the factors that determine the value and price of a coin on the market is the demand and actors on the market. These factors stems from the people, thus, how willing sellers and buyers (the actors) are to sell and buy respectively at certain high or low prices will determine the value of the coin cumulatively with time.
In the even of panic sell, these actors sell and buy at low prices thereby affecting the actual value and price of the coin. Normally, it takes time for some coins to recover from this heavy blow, whereas others do not recover at all.