Invest 100USD in BTC and BTC went down by more than 100USD. How much I lose? Can I hold? how long?

[Bitcoin]

Invest 100USD in BTC and BTC went down by more than 100USD. How much I lose? Can I hold? how long?

If I invest 100usd in BTC and let's say BTC went down next down by 200. What will happen? Would I only lose my 100 usd? OR, I also owe another 100usd?
If anyone can explain. NOTE: Super new in investment world.
Thank you.

Source: Invest 100USD in BTC and BTC went down by more than 100USD. How much I lose? Can I hold? how long?