1. Adjust the height of the strings: If the neck is bent, the height of the strings will change, and adjusting the height of the strings can solve the problem. You can adjust the height of the strings with a hex wrench or guitar adjuster.
2. Adjust the bridle: If the pitch changes due to the bending of the neck, it can be solved by adjusting the bridle. You can use the guitar adjuster to adjust the bridge.
3. Ask a professional to repair it: If you are not sure how to deal with the bending of the guitar neck, you'd better ask a professional to repair it.