Hi gayathripuram,
Thank you for reaching out Microsoft Community. We're sorry to know that your now having hardware issue with the device keyboard.
Unfortunately, there's no troubleshooting steps that can get a hardware component issue/bulging battery issue fixed and the best resolution we can suggest is to contact our Microsoft Surface Support for replacement options. Please visit this link >>https://support.microsoft.com/en-us/help/4051701/global-customer-service-phone-numbers to get direct assistance from our technical support team since we cannot process any replacement here in MS Community.
If this helps, feel free to mark this post as an answer. Otherwise don't hesitate to respond to this thread if there's anything else that needs to be addressed.
Kind Regards,
Crest_Z