if a stock goes below your investment and couple days it goes goes back up, do you still lose your investment?

I'm asking because someone mentioned to me that he had money in stock and claims that happened.

IE:

Stock at $500
Invested $200
Stock dropped to $100
Stock goes back up to $500

He claims he still has his initial investment?
I said, “This can't be true.” If that was the case, then nobody would ever lose their money in stocks.