I made the same mistake, I sold 20 eth at a price of $ 180 and now it costs $ 265, I bought at a price of $ 255 and the price is $ 210, and now I still hold it until the price is over $ 300
The classic mistake when someone tries to trade without analyzing the market.
If there is no knowledge in this area, then you can read the opinions of 3-4 experienced traders (now there are many Telegram channels) and make your decision.
It's much better than trading at random.
It takes time to make it nearly perfect (actually it can't be perfect). What happens to that person is not he doesn't have knowledge in trading but he is just in the wrong timing when selling his coins. Actually, we don't know what will happen next, the same thing it happens to him.