Hey Sunny!
I definitely get how important it is for Touch ID to be operating the way it's intended. Unfortunately, as Johnathan mentioned, we are unable to provide support with hardware physical damage, we can only provide advice on getting it repaired.
My advice would be to reach out to your insurance company (for example Asurion) if you have insurance through your cellular carrier, if you have service and see if you're eligible to file a claim for damage. If they do not provide you with a resolution, you can always visit http://support.apple.com/repair and click on the "Start a repair request" button. The flow will provide you with solutions such as Contacting Apple Support, visiting a Authorized Retailer, etc.