Hi Mohamed585,
Welcome to Apple Support Communities. We understand that you're having an issue with the gasket/seal around your MacBook Air. We'd like to point you in the right direction for help with this.
From what you've shared, it would be best to get your MacBook evaluated for service at a local Apple Store or Apple Authorized Service Provider. This will allow you to know the best ways to proceed with this and learn about any possible repair costs if needed.
Depending on where you're located, you can look here for information on repairs and locations: Mac Repair & Service - Apple Support
Otherwise, check out local Apple Authorized Service Providers here: https://locate.apple.com/choose-country-region
Hope that helps.
Cheers!