What should I do if the bottle cap of Dior perfume is opened below?

In this case, you can try the following solutions:

1. Stick the gap under the bottle cap with glue or tape, and then use it when it is dry.

2. If the crack is large, you can wrap the crack under the bottle cap with transparent tape or glue to increase its strength.

3. If the crack can't be repaired, you can consider replacing the bottle cap or pouring the perfume into other bottles for preservation.